The NHIS is a continuous, nationwide in-person survey of approximately 35,000 households, or about 87,500 persons, in the civilian non-institutionalized population. This sample size can fluctuate based on available funding. The NHIS over samples African-American and Hispanic respondents. NCI periodically sponsors a Cancer Control Supplement (CCS) on the NHIS, which is administered to the sample adult in the selected household.