Every 10 years, the United States counts itself – and 72 years later the data is made public. On April 2, the 1940 census was released.

Why count? Why 72 years till release?

The U.S. started counting in 1790. Back then the only name deemed important was the head of the household, with the other folk living in the house noted by a mark in the appropriate column by age. Females had their own column, as did slaves. Genealogists are not at all fond of the “slash census,” as these are known, but they constantly remind themselves the public records they use were not created for them.

The census changed dramatically in 1850, when, for the first time, everyone living in the household was listed by name, along with their age, sex, occupation, birthplace, parent’s birthplace, mother tongue, and education.

The census is a remarkable document. Taken as a whole through the centuries, it tracks the economic development and the growth of the country. In 1930, the year after the crash, families were asked if they had a radio, at that time a pricey piece of technology.

Until recently, each census included new states. The count shows our country not only growing dramatically, but also moving off the east coast, and settling “the West,” which kept moving further west (Civil War soldiers were often paid in land rather than cash). It shows the great migration of African-Americans north after WWI (many came to Chicago), and the dustbowl moves of the 1930s (which show up on this census).

The census is a remarkable document because it is the only one that asks of everyone in our enormous country the same questions at the same time: What was your age at your last birthday? Where were you born? Where were your parents born? Do you read and write English? When did you immigrate? Are you naturalized? How many children have you had? How many living? How old were you at your first marriage? What is your occupation? Do you work for wages or are you an owner? Do you rent or own? What is your rent? What is your house worth?

Different questions appear and disappear on each census, but by fitting together the clues, the picture of individuals and families emerges.

The 1940 census counted 132 million people in 48 states. “Enumerators” asked 33 questions of each person in the country. The questions asked reflect the concerns of a country 10 years after the crash, seven years into WPA programs, and six years after the Midwest droughts struck. (Internationally, Hitler was in power in Germany and had invaded Poland in 1939) Previous censuses asked 3-5 questions about occupation/employment. This census asked 13 questions, and made specific mention of asking this question of all persons 14 and over.

The 1940 census also includes questions about their residence on April 1, 1935 – the first time any question of this sort was asked on a census. Historically, states often did their own census on the 5-year mark, but the federal census covered the entire U.S. and was able to capture some of the disruption caused by the crash and dustbowl.

The 1940 census is also special for seniors. Given our increasing life span, even with the 72-year delay, many folks get to say, “Look, it’s me,” and grin about information recorded long ago.

1940 was a world away. This was pre-WWII, so there were kings and queens in many countries, including countries that no longer exist. Japan was an empire, and Roosevelt was the president. Segregated schools and cities were the norm, and the census asked if you were black. Also, interestingly, many of the institutions and inventions that we take for granted, started during the 1930s, the decade that made the world of the 1940 census: scotch tape, the radio, the Wizard of Oz.

Should you like to have a look at it yourself, the 1940 census will be accessible free of charge through Ancestry.com and FamilySearch.org. It will not be indexed at the time of release, though an army of volunteers has signed on to do so. To find your family prior to the index, you can use the following tool Ð Unified 1940 Census EDFinder Ð found at www.stevemorse.org/census/unified.html. Follow the instructions in the tutorial.

So why 72 years? When the date was set, it was thought that 72 years was a reasonable amount of time to wait “because nearly everyone in the census would be dead.”

Happily, that isn’t the case.