An indispensable guide and set of data from Cornell University. "The estimates provided on this website are based on analyses of three different data sources: the American Community Survey (ACS), Current Population Survey (CPS), and Census 2000. Each data source has different strengths and use different questions to identify disability. The data source you should use depends on the type of information you are interested in." This helps you select the best data depending on your specific needs.

http://www.disabilitystatistics.org/