Home improvement projects have a significant impact on the housing stock, affecting housing values and improving the standard of living. Also, the home improvement industry plays an important role in the overall US economy. Home improvement expenditure accounts for almost 2% of the US gross domestic product. This market has shown significant growth in recent years. The Joint Center for Housing Studies estimates that from 1995 to 1999, expenditure on home improvements grew from $150 billion to $180 billion.