The Commercial Buildings Energy Consumption Survey (CBECS) is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures. Commercial buildings include all buildings in which at least half of the floorspace is used for a purpose that is not residential, industrial, or agricultural, so they include building types that might not traditionally be considered "commercial," such as schools, correctional institutions, and buildings used for religious worship. The CBECS was first conducted in 1979; the eighth survey was conducted in 2003. CBECS conducts surveys on a quadrennial basis. CBECS data is extensive, but somewhat to difficult to use; for a more readable, easier-to-use presentation of the CBECS data, see BuildingBenchmarks.com