Individual information from the U.S. Census will be released Monday — that’s the 1940 Census.

“The Census [Bureau] is careful to guard personal information for a certain number of years, and the number of years they keep it private is 72 years, and this is the year they release it," said Mike Irwin, a demographer and associate professor of sociology at Duquesne University.

According to Irwin, the data from that census, that had been previously available, tended to be basic information such as averages and aggregates. “This will give us individual information from families and households in 1940,” Irwin said.

Irwin said that in 1940, for the first time, they sought some very specific information from residents by asking 5% of the population a set of in-depth social and economic questions.

“It was important because we were just coming out of the depression at that point,” Irwin said, “and they really wanted to know a lot more information about where people were employed, how long they’ve been unemployed, where they had migrated to in the previous decade, and they were using all of that for planning purposes to get out of the depression.”

Irwin said this information can be a treasure trove for sociologists, genealogists and other researchers.

“1940 was a watershed year for a lot of people,” Irwin said. “Our economy was much different after the war. After the war the pace of change began to increase. Family structure changed, the length of marriage, fertility, all of that changed dramatically. So, it’s a really good historical and demographic benchmark year.”

According to Irwin the Census Bureau stopped asking the detailed questions in the 2000 Census. Instead, “we’re going out on a yearly basis and getting those detailed questions on a much more limited basis around the country,” Irwin said.