Mail return rates are used to measure participation in the decennial Census. They compare how many survey forms are completed to numbers of occupied housing units that received the mailed questionnaires.
For the 2010 Census, the national mail return rate was 79.3 percent. Return rates vary significantly across the country, with certain demographics and individual communities much less likely to return questionnaires. Counties with lower mail return rates are common throughout the Sun Belt and rural areas of Appalachia and parts of the western U.S.
Initial mail response rates, a separate measure recorded in April of Census years, are slightly lower than final mail return rates. The final rates are reported after the Census Bureau receives all initial and replacement survey questionnaires.
The following map shows mail return rates by county for the 2010 Census. Pan the map to view Alaska and Hawaii. Rates are not reported for some counties (shaded white) that use a special enumeration method.