General Social Survey
The General Social Survey (GSS) is a sociological survey used to collect data on demographic characteristics and beliefs/attitudes of United States residents 18 years and older. The survey is conducted by the National Opinion Research Center at the University of Chicago. The GSS has tracked the opinions of Americans over the last 40 years. Starting in 1977, each sample in the GSS was selected at random.
According to the General Social Survey website: "The GSS is the largest project funded by the Sociology Program of the National Science Foundation. Except for the U.S. Census, the GSS is the most frequently analyzed source of information in the social sciences."