Source: US. Bureau of the Census
Effective June 14, 2001, data were reconstructed to reflect the switch from the Standard Industrial Classification (SIC) system to the North American Industry Classification System (NAICS).
US. Bureau of the Census, Total Business: Inventories to Sales Ratio [ISRATIO], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/ISRATIO, December 5, 2016.