Source: U.S. Bureau of Economic Analysis  

Release: Gross Domestic Product  

Units:  Billions of Dollars, Seasonally Adjusted Annual Rate

Frequency:  Quarterly

BEA Account Code: A261RC
Gross domestic income is an alternative way of measuring the nation's economy, by counting the incomes earned and costs incurred in production. In theory, GDI should equal gross domestic product, but the different source data yield different results. The difference between the two measures is known as the "statistical discrepancy." BEA considers GDP more reliable because it's based on timelier, more expansive data.

Source: U.S. Bureau of Economic Analysis  

Release: Personal Income and Outlays  

Units:  Billions of Dollars, Seasonally Adjusted Annual Rate

Frequency:  Monthly

BEA Account Code: W823RC
Social security benefits include old-age, survivors, and disability insurance benefits that are distributed from the federal old-age and survivors insurance trust fund and the disability insurance trust fund.
A Guide to the National Income and Product Accounts of the United States (NIPA) - (http://www.bea.gov/national/pdf/nipaguid.pdf)