What could be the problem? Could it be mistrust of the federal government? Just a guess.
From a story by Hope Yen of The Associated Press:
Roughly 100 million households to go.Census Bureau Rolls Out New Interactive Maps Showing 2010 Census Mail Participation Rates
One week after U.S. census forms were mailed to 120 million households, about 16 percent of the nation has completed those forms and sent them back. That number puts the government on its way to matching or surpassing mail participation rates in 2000 of 72 percent, the Census Bureau said Wednesday.
The bureau will continue to accept mailed-in forms through most of April.
From May until July, it will send census-takers to each home that doesn't reply by mail, which is more costly and sometimes leads to more inaccurate responses. The Census Bureau has estimated it would save $1.5 billion in follow-up visits if everyone who receives a census form mails it back.