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This undated image provided by the National Archives and Records Administration shows a form used in the 1940 Census. The 1940 Census will be released to the public on Monday, April 2, 2012. While a name index will not be immediately available to search, tens of thousands of researchers across the country are expected to go on a massive genealogical hunt through the digitized records for details on 132 million people. (AP Photo/National Archives and Records Administration)

1940 census records released online

The 1940 census records were released Apr. 2, with more than 21 million people alive in the U.S. and Puerto Rico.