A.1.3. Bureau of the Census and Household Numbers

The number of households by state was published by the U.S. Census Bureau, in “The Demographic Trends in the 20th Century”. The table provides us with the number of households by state for each decade of the 20th century (1900, 1910, 1920, and so on to 2000). The intercensal estimates of the household population are produced by the U.S. Bureau of the Census for each year between 1981 and 1989 45 and again between 1991 and 1998. 46

The intercensal estimates have been retrieved from 1911 to 1979 by assuming for each decade a linear progression of the type V n = V 0 * (1 + r) n , where n = 1 to 9 and r = (V 10 / V 0)1/10 - 1. Because the interpolated series assumes constant the magnitude of the annual change, this method of estimation is also called ‘straight-line interpolation’. Note that it is the default option of the Bureau of Economic Analysis, when no other data source is available.

Labeled N*, the state estimates of households for 2001, 2002 and 2003 were obtained by inflating the Census state figure for year 2000 with the average growth rate of the household population over the 1990-2000 decade.

Before 1960, the data for Alaska and Hawaii are missing in the publications mentioned above. The missing data were replaced by the number of occupied dwelling units released in the following publications: (1) the 1950 Census of Housing 47 for both Alaska and Hawaii, (2) the 1940 Census of Population for Alaska in 1940, and (3) the 1940 Census of Housing, for Hawaii in 1940, 1930, and 1920.

Between 1913 and 1939, Alaska’s number of households is assumed to be proportional to the share of Alaska's households in the U.S. total in 1940 (as 1940 is the earliest year this data is available). Similarly, estimates of N* for Hawaii between 1913 and 1919 are hooked to Hawaii’s population share in the national aggregate in 1920.

The main issue relative to the series N* concerns the equation of one return per household. Because most of the time more than one tax return is filed per household, the initial time-series of households was scaled up so that the national aggregates fit Piketty and Saez series, keeping untouched the state proportions.

Notes
45.

The estimates are consistent with Current Population Report Series P25-1123, issued in October 1994.

46.

Census Bureau’s “Estimates of Housing Units, Households, Households by Age of Householder, and Persons per Household of States: Annual Time Series, July 1, 1991 to July 1, 1998”. Publication ST-98-51.

47.

General Characteristics, Part 7.