H/t to Ed O’Keefe of The Washington Post:

The 2010 Census response rate matched returns for the 2000 Census, the U.S. Census Bureau said Wednesday.

Seventy-two percent of American households returned questionnaires by last week and 28 states had higher response rates than 10 years ago. Seven of the 10 most populous counties matched their 2000 response rates as did eight of the 10 most populous cities, the Census Bureau said.

Census Director Robert Groves estimated that between 46 million and 49 million households did not return questionnaires. Temporary census takers hired by the agency will hit the streets starting this week and will visit those addresses up to six times to get answers. The agency will further outline those plans at a news conference Monday.

Groves said he anticipates critics will question why this year’s results only matched the 2000 response rates despite a multimillion-dollar advertising and outreach campaign, but he called this year’s results “unbelievable” because survey response rates have dropped significantly in the past decade.

Socioeconomic concerns rather than race or ethnicity appeared to drive lower response rates, Groves said. Less-educated, lower-income households appeared to respond less. The nation’s foreclosure crisis also contributed to the lower rates, he said.

The total cost of 2010 Census operations — budgeted for about $14 billion — will be known once officials get a complete tally of households that did not respond, Groves said.