Table Data - Yields on Corporate Bonds, Highest Rating for United States
| Title | Yields on Corporate Bonds, Highest Rating for United States |
|---|---|
| Series ID | M13035USM156NNBR |
| Source | National Bureau of Economic Research |
| Release | NBER Macrohistory Database (Not a Press Release) |
| Seasonal Adjustment | Not Seasonally Adjusted |
| Frequency | Monthly |
| Units | Percent |
| Date Range | 1919-01-01 to 1968-12-01 |
| Last Updated | 2012-08-20 8:17 AM CDT |
| Notes |
| DATE | VALUE |
|---|---|
| 1919-01-01 | 5.35 |
| 1919-02-01 | 5.35 |
| 1919-03-01 | 5.39 |
| 1919-04-01 | 5.44 |
| 1919-05-01 | 5.39 |
| 1919-06-01 | 5.40 |
| 1919-07-01 | 5.44 |
| 1919-08-01 | 5.56 |
| 1919-09-01 | 5.60 |
| 1919-10-01 | 5.54 |
| 1919-11-01 | 5.66 |
| 1919-12-01 | 5.73 |
| 1920-01-01 | 5.75 |
| 1920-02-01 | 5.86 |
| 1920-03-01 | 5.92 |
| 1920-04-01 | 6.04 |
| 1920-05-01 | 6.25 |
| 1920-06-01 | 6.38 |
| 1920-07-01 | 6.34 |
| 1920-08-01 | 6.30 |
| 1920-09-01 | 6.22 |
| 1920-10-01 | 6.05 |
| 1920-11-01 | 6.08 |
| 1920-12-01 | 6.26 |
| 1921-01-01 | 6.14 |
| 1921-02-01 | 6.08 |
| 1921-03-01 | 6.08 |
| 1921-04-01 | 6.06 |
| 1921-05-01 | 6.11 |
| 1921-06-01 | 6.18 |
| 1921-07-01 | 6.12 |
| 1921-08-01 | 5.99 |
| 1921-09-01 | 5.93 |
| 1921-10-01 | 5.84 |
| 1921-11-01 | 5.60 |
| 1921-12-01 | 5.50 |
| 1922-01-01 | 5.34 |
| 1922-02-01 | 5.29 |
| 1922-03-01 | 5.23 |
| 1922-04-01 | 5.15 |
| 1922-05-01 | 5.13 |
| 1922-06-01 | 5.08 |
| 1922-07-01 | 5.00 |
| 1922-08-01 | 4.96 |
| 1922-09-01 | 4.93 |
| 1922-10-01 | 4.97 |
| 1922-11-01 | 5.09 |
| 1922-12-01 | 5.08 |
| 1923-01-01 | 5.04 |
| 1923-02-01 | 5.07 |
| 1923-03-01 | 5.18 |
| 1923-04-01 | 5.22 |
| 1923-05-01 | 5.16 |
| 1923-06-01 | 5.15 |
| 1923-07-01 | 5.14 |
| 1923-08-01 | 5.08 |
| 1923-09-01 | 5.12 |
| 1923-10-01 | 5.11 |
| 1923-11-01 | 5.09 |
| 1923-12-01 | 5.09 |
| 1924-01-01 | 5.09 |
| 1924-02-01 | 5.09 |
| 1924-03-01 | 5.10 |
| 1924-04-01 | 5.08 |
| 1924-05-01 | 5.04 |
| 1924-06-01 | 4.99 |
| 1924-07-01 | 4.95 |
| 1924-08-01 | 4.95 |
| 1924-09-01 | 4.95 |
| 1924-10-01 | 4.92 |
| 1924-11-01 | 4.94 |
| 1924-12-01 | 4.95 |
| 1925-01-01 | 4.95 |
| 1925-02-01 | 4.95 |
| 1925-03-01 | 4.91 |
| 1925-04-01 | 4.87 |
| 1925-05-01 | 4.83 |
| 1925-06-01 | 4.83 |
| 1925-07-01 | 4.87 |
| 1925-08-01 | 4.90 |
| 1925-09-01 | 4.87 |
| 1925-10-01 | 4.85 |
| 1925-11-01 | 4.84 |
| 1925-12-01 | 4.85 |
| 1926-01-01 | 4.82 |
| 1926-02-01 | 4.77 |
| 1926-03-01 | 4.79 |
| 1926-04-01 | 4.74 |
| 1926-05-01 | 4.71 |
| 1926-06-01 | 4.72 |
| 1926-07-01 | 4.71 |
| 1926-08-01 | 4.72 |
| 1926-09-01 | 4.72 |
| 1926-10-01 | 4.71 |
| 1926-11-01 | 4.68 |
| 1926-12-01 | 4.68 |
| 1927-01-01 | 4.66 |
| 1927-02-01 | 4.67 |
| 1927-03-01 | 4.62 |
| 1927-04-01 | 4.58 |
| 1927-05-01 | 4.57 |
| 1927-06-01 | 4.58 |
| 1927-07-01 | 4.60 |
| 1927-08-01 | 4.56 |
| 1927-09-01 | 4.54 |
| 1927-10-01 | 4.51 |
| 1927-11-01 | 4.49 |
| 1927-12-01 | 4.46 |
| 1928-01-01 | 4.46 |
| 1928-02-01 | 4.46 |
| 1928-03-01 | 4.46 |
| 1928-04-01 | 4.46 |
| 1928-05-01 | 4.49 |
| 1928-06-01 | 4.57 |
| 1928-07-01 | 4.61 |
| 1928-08-01 | 4.64 |
| 1928-09-01 | 4.61 |
| 1928-10-01 | 4.61 |
| 1928-11-01 | 4.58 |
| 1928-12-01 | 4.61 |
| 1929-01-01 | 4.62 |
| 1929-02-01 | 4.66 |
| 1929-03-01 | 4.70 |
| 1929-04-01 | 4.69 |
| 1929-05-01 | 4.70 |
| 1929-06-01 | 4.77 |
| 1929-07-01 | 4.77 |
| 1929-08-01 | 4.79 |
| 1929-09-01 | 4.80 |
| 1929-10-01 | 4.77 |
| 1929-11-01 | 4.76 |
| 1929-12-01 | 4.67 |
| 1930-01-01 | 4.66 |
| 1930-02-01 | 4.69 |
| 1930-03-01 | 4.62 |
| 1930-04-01 | 4.60 |
| 1930-05-01 | 4.60 |
| 1930-06-01 | 4.57 |
| 1930-07-01 | 4.52 |
| 1930-08-01 | 4.47 |
| 1930-09-01 | 4.42 |
| 1930-10-01 | 4.42 |
| 1930-11-01 | 4.47 |
| 1930-12-01 | 4.52 |
| 1931-01-01 | 4.42 |
| 1931-02-01 | 4.43 |
| 1931-03-01 | 4.39 |
| 1931-04-01 | 4.40 |
| 1931-05-01 | 4.37 |
| 1931-06-01 | 4.36 |
| 1931-07-01 | 4.36 |
| 1931-08-01 | 4.40 |
| 1931-09-01 | 4.55 |
| 1931-10-01 | 4.99 |
| 1931-11-01 | 4.94 |
| 1931-12-01 | 5.32 |
| 1932-01-01 | 5.20 |
| 1932-02-01 | 5.23 |
| 1932-03-01 | 4.98 |
| 1932-04-01 | 5.17 |
| 1932-05-01 | 5.36 |
| 1932-06-01 | 5.41 |
| 1932-07-01 | 5.26 |
| 1932-08-01 | 4.91 |
| 1932-09-01 | 4.70 |
| 1932-10-01 | 4.64 |
| 1932-11-01 | 4.63 |
| 1932-12-01 | 4.59 |
| 1933-01-01 | 4.44 |
| 1933-02-01 | 4.48 |
| 1933-03-01 | 4.68 |
| 1933-04-01 | 4.78 |
| 1933-05-01 | 4.63 |
| 1933-06-01 | 4.46 |
| 1933-07-01 | 4.36 |
| 1933-08-01 | 4.30 |
| 1933-09-01 | 4.36 |
| 1933-10-01 | 4.34 |
| 1933-11-01 | 4.54 |
| 1933-12-01 | 4.50 |
| 1934-01-01 | 4.35 |
| 1934-02-01 | 4.20 |
| 1934-03-01 | 4.13 |
| 1934-04-01 | 4.07 |
| 1934-05-01 | 4.01 |
| 1934-06-01 | 3.93 |
| 1934-07-01 | 3.89 |
| 1934-08-01 | 3.93 |
| 1934-09-01 | 3.96 |
| 1934-10-01 | 3.90 |
| 1934-11-01 | 3.86 |
| 1934-12-01 | 3.81 |
| 1935-01-01 | 3.77 |
| 1935-02-01 | 3.69 |
| 1935-03-01 | 3.67 |
| 1935-04-01 | 3.66 |
| 1935-05-01 | 3.65 |
| 1935-06-01 | 3.61 |
| 1935-07-01 | 3.56 |
| 1935-08-01 | 3.60 |
| 1935-09-01 | 3.59 |
| 1935-10-01 | 3.52 |
| 1935-11-01 | 3.47 |
| 1935-12-01 | 3.44 |
| 1936-01-01 | 3.37 |
| 1936-02-01 | 3.32 |
| 1936-03-01 | 3.29 |
| 1936-04-01 | 3.29 |
| 1936-05-01 | 3.27 |
| 1936-06-01 | 3.24 |
| 1936-07-01 | 3.23 |
| 1936-08-01 | 3.21 |
| 1936-09-01 | 3.18 |
| 1936-10-01 | 3.18 |
| 1936-11-01 | 3.15 |
| 1936-12-01 | 3.10 |
| 1937-01-01 | 3.10 |
| 1937-02-01 | 3.22 |
| 1937-03-01 | 3.32 |
| 1937-04-01 | 3.42 |
| 1937-05-01 | 3.33 |
| 1937-06-01 | 3.28 |
| 1937-07-01 | 3.25 |
| 1937-08-01 | 3.24 |
| 1937-09-01 | 3.28 |
| 1937-10-01 | 3.27 |
| 1937-11-01 | 3.24 |
| 1937-12-01 | 3.21 |
| 1938-01-01 | 3.17 |
| 1938-02-01 | 3.20 |
| 1938-03-01 | 3.22 |
| 1938-04-01 | 3.30 |
| 1938-05-01 | 3.22 |
| 1938-06-01 | 3.26 |
| 1938-07-01 | 3.22 |
| 1938-08-01 | 3.18 |
| 1938-09-01 | 3.21 |
| 1938-10-01 | 3.15 |
| 1938-11-01 | 3.10 |
| 1938-12-01 | 3.08 |
| 1939-01-01 | 3.01 |
| 1939-02-01 | 3.00 |
| 1939-03-01 | 2.99 |
| 1939-04-01 | 3.02 |
| 1939-05-01 | 2.97 |
| 1939-06-01 | 2.92 |
| 1939-07-01 | 2.89 |
| 1939-08-01 | 2.93 |
| 1939-09-01 | 3.25 |
| 1939-10-01 | 3.15 |
| 1939-11-01 | 3.00 |
| 1939-12-01 | 2.94 |
| 1940-01-01 | 2.88 |
| 1940-02-01 | 2.86 |
| 1940-03-01 | 2.84 |
| 1940-04-01 | 2.82 |
| 1940-05-01 | 2.93 |
| 1940-06-01 | 2.96 |
| 1940-07-01 | 2.88 |
| 1940-08-01 | 2.85 |
| 1940-09-01 | 2.82 |
| 1940-10-01 | 2.79 |
| 1940-11-01 | 2.75 |
| 1940-12-01 | 2.71 |
| 1941-01-01 | 2.75 |
| 1941-02-01 | 2.78 |
| 1941-03-01 | 2.80 |
| 1941-04-01 | 2.82 |
| 1941-05-01 | 2.81 |
| 1941-06-01 | 2.77 |
| 1941-07-01 | 2.74 |
| 1941-08-01 | 2.74 |
| 1941-09-01 | 2.75 |
| 1941-10-01 | 2.73 |
| 1941-11-01 | 2.72 |
| 1941-12-01 | 2.80 |
| 1942-01-01 | 2.83 |
| 1942-02-01 | 2.85 |
| 1942-03-01 | 2.86 |
| 1942-04-01 | 2.83 |
| 1942-05-01 | 2.85 |
| 1942-06-01 | 2.85 |
| 1942-07-01 | 2.83 |
| 1942-08-01 | 2.81 |
| 1942-09-01 | 2.80 |
| 1942-10-01 | 2.80 |
| 1942-11-01 | 2.79 |
| 1942-12-01 | 2.81 |
| 1943-01-01 | 2.79 |
| 1943-02-01 | 2.77 |
| 1943-03-01 | 2.76 |
| 1943-04-01 | 2.76 |
| 1943-05-01 | 2.74 |
| 1943-06-01 | 2.72 |
| 1943-07-01 | 2.69 |
| 1943-08-01 | 2.69 |
| 1943-09-01 | 2.69 |
| 1943-10-01 | 2.70 |
| 1943-11-01 | 2.71 |
| 1943-12-01 | 2.74 |
| 1944-01-01 | 2.72 |
| 1944-02-01 | 2.74 |
| 1944-03-01 | 2.74 |
| 1944-04-01 | 2.74 |
| 1944-05-01 | 2.73 |
| 1944-06-01 | 2.73 |
| 1944-07-01 | 2.72 |
| 1944-08-01 | 2.71 |
| 1944-09-01 | 2.72 |
| 1944-10-01 | 2.72 |
| 1944-11-01 | 2.72 |
| 1944-12-01 | 2.70 |
| 1945-01-01 | 2.69 |
| 1945-02-01 | 2.65 |
| 1945-03-01 | 2.62 |
| 1945-04-01 | 2.61 |
| 1945-05-01 | 2.62 |
| 1945-06-01 | 2.61 |
| 1945-07-01 | 2.60 |
| 1945-08-01 | 2.61 |
| 1945-09-01 | 2.62 |
| 1945-10-01 | 2.62 |
| 1945-11-01 | 2.62 |
| 1945-12-01 | 2.61 |
| 1946-01-01 | 2.54 |
| 1946-02-01 | 2.48 |
| 1946-03-01 | 2.47 |
| 1946-04-01 | 2.46 |
| 1946-05-01 | 2.51 |
| 1946-06-01 | 2.49 |
| 1946-07-01 | 2.48 |
| 1946-08-01 | 2.51 |
| 1946-09-01 | 2.58 |
| 1946-10-01 | 2.60 |
| 1946-11-01 | 2.59 |
| 1946-12-01 | 2.61 |
| 1947-01-01 | 2.57 |
| 1947-02-01 | 2.55 |
| 1947-03-01 | 2.55 |
| 1947-04-01 | 2.53 |
| 1947-05-01 | 2.53 |
| 1947-06-01 | 2.55 |
| 1947-07-01 | 2.55 |
| 1947-08-01 | 2.56 |
| 1947-09-01 | 2.61 |
| 1947-10-01 | 2.70 |
| 1947-11-01 | 2.77 |
| 1947-12-01 | 2.86 |
| 1948-01-01 | 2.86 |
| 1948-02-01 | 2.85 |
| 1948-03-01 | 2.83 |
| 1948-04-01 | 2.78 |
| 1948-05-01 | 2.76 |
| 1948-06-01 | 2.76 |
| 1948-07-01 | 2.81 |
| 1948-08-01 | 2.84 |
| 1948-09-01 | 2.84 |
| 1948-10-01 | 2.84 |
| 1948-11-01 | 2.84 |
| 1948-12-01 | 2.79 |
| 1949-01-01 | 2.71 |
| 1949-02-01 | 2.71 |
| 1949-03-01 | 2.70 |
| 1949-04-01 | 2.70 |
| 1949-05-01 | 2.71 |
| 1949-06-01 | 2.71 |
| 1949-07-01 | 2.67 |
| 1949-08-01 | 2.62 |
| 1949-09-01 | 2.60 |
| 1949-10-01 | 2.61 |
| 1949-11-01 | 2.60 |
| 1949-12-01 | 2.58 |
| 1950-01-01 | 2.57 |
| 1950-02-01 | 2.58 |
| 1950-03-01 | 2.58 |
| 1950-04-01 | 2.60 |
| 1950-05-01 | 2.61 |
| 1950-06-01 | 2.62 |
| 1950-07-01 | 2.65 |
| 1950-08-01 | 2.61 |
| 1950-09-01 | 2.64 |
| 1950-10-01 | 2.67 |
| 1950-11-01 | 2.67 |
| 1950-12-01 | 2.67 |
| 1951-01-01 | 2.66 |
| 1951-02-01 | 2.66 |
| 1951-03-01 | 2.78 |
| 1951-04-01 | 2.87 |
| 1951-05-01 | 2.88 |
| 1951-06-01 | 2.94 |
| 1951-07-01 | 2.94 |
| 1951-08-01 | 2.88 |
| 1951-09-01 | 2.84 |
| 1951-10-01 | 2.89 |
| 1951-11-01 | 2.96 |
| 1951-12-01 | 3.01 |
| 1952-01-01 | 2.98 |
| 1952-02-01 | 2.93 |
| 1952-03-01 | 2.96 |
| 1952-04-01 | 2.93 |
| 1952-05-01 | 2.93 |
| 1952-06-01 | 2.94 |
| 1952-07-01 | 2.95 |
| 1952-08-01 | 2.94 |
| 1952-09-01 | 2.95 |
| 1952-10-01 | 3.01 |
| 1952-11-01 | 2.98 |
| 1952-12-01 | 2.97 |
| 1953-01-01 | 3.02 |
| 1953-02-01 | 3.07 |
| 1953-03-01 | 3.12 |
| 1953-04-01 | 3.23 |
| 1953-05-01 | 3.34 |
| 1953-06-01 | 3.40 |
| 1953-07-01 | 3.28 |
| 1953-08-01 | 3.24 |
| 1953-09-01 | 3.29 |
| 1953-10-01 | 3.16 |
| 1953-11-01 | 3.11 |
| 1953-12-01 | 3.13 |
| 1954-01-01 | 3.06 |
| 1954-02-01 | 2.95 |
| 1954-03-01 | 2.86 |
| 1954-04-01 | 2.85 |
| 1954-05-01 | 2.88 |
| 1954-06-01 | 2.90 |
| 1954-07-01 | 2.89 |
| 1954-08-01 | 2.87 |
| 1954-09-01 | 2.89 |
| 1954-10-01 | 2.87 |
| 1954-11-01 | 2.89 |
| 1954-12-01 | 2.90 |
| 1955-01-01 | 2.93 |
| 1955-02-01 | 2.99 |
| 1955-03-01 | 3.02 |
| 1955-04-01 | 3.01 |
| 1955-05-01 | 3.04 |
| 1955-06-01 | 3.05 |
| 1955-07-01 | 3.06 |
| 1955-08-01 | 3.11 |
| 1955-09-01 | 3.13 |
| 1955-10-01 | 3.10 |
| 1955-11-01 | 3.10 |
| 1955-12-01 | 3.15 |
| 1956-01-01 | 3.11 |
| 1956-02-01 | 3.08 |
| 1956-03-01 | 3.10 |
| 1956-04-01 | 3.24 |
| 1956-05-01 | 3.28 |
| 1956-06-01 | 3.27 |
| 1956-07-01 | 3.28 |
| 1956-08-01 | 3.43 |
| 1956-09-01 | 3.56 |
| 1956-10-01 | 3.59 |
| 1956-11-01 | 3.69 |
| 1956-12-01 | 3.75 |
| 1957-01-01 | 3.77 |
| 1957-02-01 | 3.67 |
| 1957-03-01 | 3.66 |
| 1957-04-01 | 3.67 |
| 1957-05-01 | 3.74 |
| 1957-06-01 | 3.91 |
| 1957-07-01 | 3.99 |
| 1957-08-01 | 4.10 |
| 1957-09-01 | 4.12 |
| 1957-10-01 | 4.10 |
| 1957-11-01 | 4.08 |
| 1957-12-01 | 3.81 |
| 1958-01-01 | 3.60 |
| 1958-02-01 | 3.59 |
| 1958-03-01 | 3.63 |
| 1958-04-01 | 3.60 |
| 1958-05-01 | 3.57 |
| 1958-06-01 | 3.57 |
| 1958-07-01 | 3.67 |
| 1958-08-01 | 3.85 |
| 1958-09-01 | 4.09 |
| 1958-10-01 | 4.11 |
| 1958-11-01 | 4.09 |
| 1958-12-01 | 4.08 |
| 1959-01-01 | 4.12 |
| 1959-02-01 | 4.14 |
| 1959-03-01 | 4.13 |
| 1959-04-01 | 4.23 |
| 1959-05-01 | 4.37 |
| 1959-06-01 | 4.46 |
| 1959-07-01 | 4.47 |
| 1959-08-01 | 4.43 |
| 1959-09-01 | 4.52 |
| 1959-10-01 | 4.57 |
| 1959-11-01 | 4.56 |
| 1959-12-01 | 4.58 |
| 1960-01-01 | 4.61 |
| 1960-02-01 | 4.56 |
| 1960-03-01 | 4.49 |
| 1960-04-01 | 4.45 |
| 1960-05-01 | 4.46 |
| 1960-06-01 | 4.45 |
| 1960-07-01 | 4.41 |
| 1960-08-01 | 4.28 |
| 1960-09-01 | 4.25 |
| 1960-10-01 | 4.30 |
| 1960-11-01 | 4.31 |
| 1960-12-01 | 4.35 |
| 1961-01-01 | 4.32 |
| 1961-02-01 | 4.27 |
| 1961-03-01 | 4.22 |
| 1961-04-01 | 4.25 |
| 1961-05-01 | 4.27 |
| 1961-06-01 | 4.33 |
| 1961-07-01 | 4.41 |
| 1961-08-01 | 4.45 |
| 1961-09-01 | 4.45 |
| 1961-10-01 | 4.42 |
| 1961-11-01 | 4.39 |
| 1961-12-01 | 4.42 |
| 1962-01-01 | 4.42 |
| 1962-02-01 | 4.42 |
| 1962-03-01 | 4.39 |
| 1962-04-01 | 4.33 |
| 1962-05-01 | 4.28 |
| 1962-06-01 | 4.28 |
| 1962-07-01 | 4.34 |
| 1962-08-01 | 4.35 |
| 1962-09-01 | 4.32 |
| 1962-10-01 | 4.28 |
| 1962-11-01 | 4.25 |
| 1962-12-01 | 4.24 |
| 1963-01-01 | 4.21 |
| 1963-02-01 | 4.19 |
| 1963-03-01 | 4.19 |
| 1963-04-01 | 4.21 |
| 1963-05-01 | 4.22 |
| 1963-06-01 | 4.23 |
| 1963-07-01 | 4.26 |
| 1963-08-01 | 4.29 |
| 1963-09-01 | 4.31 |
| 1963-10-01 | 4.32 |
| 1963-11-01 | 4.33 |
| 1963-12-01 | 4.35 |
| 1964-01-01 | 4.37 |
| 1964-02-01 | 4.36 |
| 1964-03-01 | 4.38 |
| 1964-04-01 | 4.40 |
| 1964-05-01 | 4.41 |
| 1964-06-01 | 4.41 |
| 1964-07-01 | 4.40 |
| 1964-08-01 | 4.41 |
| 1964-09-01 | 4.42 |
| 1964-10-01 | 4.42 |
| 1964-11-01 | 4.43 |
| 1964-12-01 | 4.44 |
| 1965-01-01 | 4.43 |
| 1965-02-01 | 4.41 |
| 1965-03-01 | 4.42 |
| 1965-04-01 | 4.43 |
| 1965-05-01 | 4.44 |
| 1965-06-01 | 4.46 |
| 1965-07-01 | 4.48 |
| 1965-08-01 | 4.49 |
| 1965-09-01 | 4.52 |
| 1965-10-01 | 4.56 |
| 1965-11-01 | 4.60 |
| 1965-12-01 | 4.68 |
| 1966-01-01 | 4.74 |
| 1966-02-01 | 4.78 |
| 1966-03-01 | 4.92 |
| 1966-04-01 | 4.96 |
| 1966-05-01 | 4.98 |
| 1966-06-01 | 5.07 |
| 1966-07-01 | 5.16 |
| 1966-08-01 | 5.31 |
| 1966-09-01 | 5.49 |
| 1966-10-01 | 5.41 |
| 1966-11-01 | 5.35 |
| 1966-12-01 | 5.39 |
| 1967-01-01 | 5.20 |
| 1967-02-01 | 5.03 |
| 1967-03-01 | 5.13 |
| 1967-04-01 | 5.11 |
| 1967-05-01 | 5.24 |
| 1967-06-01 | 5.44 |
| 1967-07-01 | 5.58 |
| 1967-08-01 | 5.62 |
| 1967-09-01 | 5.65 |
| 1967-10-01 | 5.82 |
| 1967-11-01 | 6.07 |
| 1967-12-01 | 6.19 |
| 1968-01-01 | 6.17 |
| 1968-02-01 | 6.10 |
| 1968-03-01 | 6.11 |
| 1968-04-01 | 6.21 |
| 1968-05-01 | 6.27 |
| 1968-06-01 | 6.28 |
| 1968-07-01 | 6.24 |
| 1968-08-01 | 6.02 |
| 1968-09-01 | 5.97 |
| 1968-10-01 | 6.09 |
| 1968-11-01 | 6.19 |
| 1968-12-01 | 6.45 |