At least 330 million people lived in the United States as of April, according to a Census Bureau estimate released Tuesday that will serve as one of the first accuracy checks for forthcoming decennial census results.

The agency produces the estimate, referred to as demographic analysis, in parallel to the count each decade. This year, outside experts are watching closely to see how much the decennial census will reflect, or miss, the total population in the United States.

Ron Jarmin, the agency’s deputy director for operations, acknowledged the “extraordinary challenges” the census faced this cycle, primarily due to the coronavirus pandemic.

“We know that data users are eager for this information, and as are we, because of the important role these quality metrics play in telling us how well we did at counting everyone once, only once and in the right place,” Jarmin said in a call with reporters.

With the stakes so high for census results — they determine distribution of House seats and guide more than $1.5 trillion in federal spending annually — the agency releases several measures of how accurately it counted the country.

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The Census Bureau builds its population estimate from birth and death records, Medicare rolls and estimates of immigration into and out of the United States. In comparison, the actual census relies on a combination of household responses and a physical count by census workers. 

Eric Jensen, who works as a senior technical expert for the Census Bureau’s demographic analysis, said the estimate will help the agency calculate the undercounts and overcounts for the decennial census.

The population estimate released Tuesday will provide one check on census results that have many unknowns around them. The agency still hasn’t said when it will be able to release the results; officials said they aimed to finalize the numbers “as close as possible” to an end-of-year statutory deadline.

However, the agency has publicly acknowledged errors in close to 1 million records that could take weeks to fix, pushing the apportionment delivery into late January.

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Last week, the agency said it would provide detailed information about self-response to the census — considered the most accurate method of responding to the count — but less detailed data about how it counted people with door-to-door workers or through administrative records.

Overall, the agency estimates that between 330 and 335 million people lived in the United States as of April 1, the reference day for the 2020 census. That’s about 20 million more people in the country than in 2010, roughly a 6 percent change. The country’s growth has slowed over the last several decades, last increasing by more than 10 percent between 1980 and 1990.

About 45 million people identify as Black, according to the estimate, which is based on limited data; the Census Bureau only produces national estimates, and can only measure by Black and non-Black population. 

For people under 30, the agency has started producing estimates of the Hispanic population, coinciding with the addition of ethnicity data to birth records in 1990. About 31 million people under 30 identify as Hispanic, which represents more than 20 percent of the population that age.