1940 Census secrets spark web frenzy

After 72 years of secrecy, interest in World War II life proved strong as millions went online to view newly released 1940 Census data.

Immediately after the records became available to the public on the National Archives website, the Associated Press reports the site received more than 22 million hits in just four hours.

Life in the 40s

Census slogan:
"You cannot know your country unless your country knows you."

New census questions:
Migration, income, fertility, education, social security, usual occupation, unemployment

15 percent of labor market, 8 million

A confidentiality rule denied public access to the records until 2012. The census data is the largest collection of digital information ever released on the government website.

View: 1940-2010: How has American changed?

(The Associated Press contributed to this report)