NEW YORK — It was on the streets of her Harlem neighborhood in the 1940s that teenager, Althea Gibson began working on the tennis skills that would take her all the way to winning Wimbledon.

But according to the 1940 census, the trailblazing athlete didn’t even exist.

There’s no record of Gibson and her family in the decennial census, the records of which were released online to the public April 2 by the U.S. National Archives after a 72-year confidentiality period lapsed.

She and her family aren’t the only ones — more than a million Black people weren’t accounted for in 1940, an undercount that had ramifications at the time on everything from the political map to the distribution of resources.

According to census reports, the Black undercount was estimated at 8.4 percent in 1940, meaning that a population counted at 12.9 million was actually more like 14.1 million. The undercount for the nonblack population was 5 percent, or about 6.3 million people. The total undercount for all races was 7.5 million.