Beginning in 1995, the definition of commercial building was changed, which caused a break in the trend. Two building types—indoor parking garages and commercial buildings on manufacturing facilities—previously included in the sample were excluded. The magnitude of the change is shown by plotting two data points for 1992; the upper data point was the reported estimate for 1992, and the lower point was the 1992 estimate adjusted to match the 1995 building definition. Statistical detail added to Figures 1 and 2 shows the estimates of buildings and floorspace and their 95% confidence ranges.