21 and for virtually all private construction expenditures except single-family residential. This segment of construction demand is naturally responsive to any fluctuations in the business cycle. However, almost half the private spending and virtually all the public spending for construction falls in a second category, namely where construction is purchased to provide necessary facilities but no monetary return is expected. Over half of all construction today is purchased by those who do not expect a profit return, and therefore economic consditions are not of overwhelming importance.