Footnotes for
S.4.a Nonfinancial Noncorporate Business (1)

(1) Estimates for 2000 and earlier periods are based on the 1987 Standard Industrial Classification System; later estimates are based on the North American Classification System.
(2) Consists of rental income of tenant-occupied housing and proprietors' income. Quasi-corporations are unincorporated enterprises that function as if they were corporations;
they primarily cover their operating costs through sales, and they keep a complete set of financial records.
(3) Government-sponsored enterprises (GSEs) consist of Federal Home Loan Banks, Fannie Mae, Freddie Mac, Federal Agricultural Mortgage Corporation, Farm Credit System,
the Financing Corporation, and the Resolution Funding Corporation, and they included the Student Loan Marketing Association until it was fully privatized in the fourth quarter of 2004.
(4) Net equity in reserves of property-casualty insurance companies.
(5) Farm houses are included in the household sector.