"Household density is the key problem in over-consumption. In 2007, the U.S. hit a new record low of 2.56 persons per household. The data show that Americans are now spending 29.6 percent more on energy per capita than in 1960, based solely on the decline in density.
SMR's study is based on its work with the "micro-data" files of the Consumer Expenditures Survey (CES), conducted by the Census Bureau on behalf of the Bureau of Labor Statistics. These large, complex files contain raw data on household spending on hundreds of products, allowing a researcher to isolate any product and compare spending patterns to the characteristics of families. SMR used data from 27,159 household interviews conducted in 2006 and 2007, the most recent available."
Thanks to Reconnecting America