The Census Bureau has rolled out the first set of numbers showing the 2010 Census mail participation rate for communities, states and the nation. The mail participation rate is the share of households that mailed back the 2010 Census forms they received. In 2000, the final mail participation rate was 72%.

For the 2010 Census as of March 23, the rate is 16%, amounting to about 21 million forms. Census Bureau director Robert Groves said the counting effort was “off to a good start,” though he also said it is too early to discern patterns in the numbers for a variety of reasons.

For example, while some Midwestern states have the highest participation rates so far, Groves noted that some parts of that region had their census forms hand-delivered earlier than the rest of the country received them. (Most households had their forms delivered early last week.) Maryland’s early participation rate also is above-average (25%) as measured, but that rate may be boosted by the fact that a census processing center is located in the state so the returned forms are being counted more rapidly, he said.

The Census Bureau has not released data showing a comparable figure for the mail participation rate at this point in time during the 2000 Census. However, the Census Bureau’s evaluation of mail response rates in the 2000 Census and evaluation of mail return rates in the 2000 Census include charts showing day-by-day participation rates in March and April. As explained in this posting about the mail participation rate, that rate falls somewhere between the mail response rate and mail return rate.

The Census Bureau will report the mail participation rate for the nation, states and localities each weekday, based on data received by 1 p.m. EDT the previous day. The reports will end April 23, when the bureau will turn its attention to its non-response follow-up effort.