ORLANDO, Fla. (AP) — No age group was undercounted as much during the last once-a-decade census as children under 5, researchers say. Sesame Street is hoping to use Count von Count to change that.

The Muppet best known as the Count is joining Elmo, Rosita and her mom, Rosa, in public service announcements filmed on the set of the long-running educational television show. The spots encourage parents of young children to make sure they and their children are counted in the 2020 census.

The public service announcements in English and Spanish started airing Monday. The head count starts for most people this Thursday.

In the ad, the Count plays a census taker. Casting for the spots was purposeful, Sesame Workshop officials said.

"Rosita is a bilingual Muppet. Elmo is popular and connected to young children and families, and the Count is so logical when it comes to being counted," said Jeanette Betancourt, Sesame Workshop’s senior vice president of U.S. Social Impact.

The Sesame Street characters join a growing group of celebrities using their influence to encourage people to be counted. Morgan Freeman made a public service announcement for census outreach efforts in Mississippi. “Hamilton" creator Lin-Manuel Miranda and U.S. Rep. Alexandria Ocasio-Cortez cut one for New York City.

Sesame Workshop also is offering fliers and information about the census that can be downloaded and distributed from its website. The television show has promoted the census every decade since 1980, when the character Maria became a census-taker in the Sesame Street neighborhood.

Demographers estimate that 4.6% percent of children under 5, or 1 million children, weren't counted in the 2010 census. The under-counting was worst in minority communities, with under-counting for Hispanic children estimated at 7.5% and for black children at 6.3%, according to researchers.

The consequences of overlooking young children in a community can be harmful since the decennial census helps determine the distribution of $1.5 trillion in federal spending, including money for schools, Head Start and family nutrition programs.

“We are hoping to really make a dent in that this time. I think that’s really, really good because certainly the children are the future," said Stephen Buckner, a senior executive at the U.S. Census Bureau. “Someone entering the first grade is going to be an eleventh grader at the next census. There’s a lot that can change in that person’s life from grade one to grade 10.”

Researchers who have examined the undercount say young children are more likely to be living in multi-generational households, living in foster care, in more than one household because of parental custody arrangements, or living in multi-unit buildings like apartments that are difficult to access.

"Our youngest Americans need and deserve the resources that are vital to get an accurate count," U.S. Rep. Katherine Clark of Massachusetts said last week.

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Adriana Gomez Licon contributed to this report from Miami.

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