It’s a truism that American houses are growing to be elephantine; many articles on McMansions point out that the average new house in America has grown in size by 46.63% since 1973. Yet the story isn’t that simple: in fact, house sizes in recent years have grown at below trend — little more than 1% a year, a big slowdown from the mid-1980s. Also, the size of multifamily apartments is reported separately and in a different fashion (in size brackets rather than exact numbers), which makes it impossible to figure out how average new dwelling sizes are changing as multifamily grows as a share of American housing starts.

|year|size|% growth*|
|1973|1660|–|
|1976|1700|0.80%|
|1979|1760|1.18%|
|1982|1710|-0.95%|
|1985|1752|0.82%|
|1988|1995|4.62%|
|1991|2075|1.34%|
|1994|2100|0.40%|
|1997|2150|0.79%|
|2000|2266|1.80%|
|2003|2330|0.94%|
|2005|2434|1.49%|
|1973-2005|+774|2.12%|

Note: Size is in square feet, average for new construction. Source: U.S. Census, “data set C25”:http://www.census.gov/const/www/charindex.html. Sample was readjusted in 2005, with the effect of tilting sample towards Sunbelt, so results are not directly comparable to earlier years.

% growth: annualized rate, over past three years.