CBS Local — A new survey has found that a third of young millennials in the U.S. aren’t convinced the Earth is actually round. The national poll reveals that 18 to 24-year-olds are the largest group in the country who refuse to accept the scientific facts of the world’s shape.

YouGov, a British market research firm, polled 8,215 adults in the United States to find out if they ever believed in the “flat Earth” movement. Only 66 percent of young millennials answered that they “always believe the world is round.” Science teachers across the U.S. will be shaking their heads after learning that nine percent of young adults answered that they have “always believed” the planet was flat.

Another nine percent said of young adults said they thought the planet was spherical but had doubts about it. In a disturbing display of indecision, 16 percent of millennials said they weren’t sure what the shape of the planet was.

Overall, only two percent of the respondents said they always thought the Earth was flat without any doubt. YouGov found that age was directly connected to Americans’ views on the shape of the world. Seventy-six percent of adults age 25-34 say they’ve always believed the Earth is round, compared to 82 percent of ages 35-44, 85 percent of ages 45-54, and 94 percent of adults 55 and over.

Income seemed to play a role in people’s beliefs as well. Ninety-two percent of adults making over $80,000 believed the Earth is round, compared to only 79 percent of adults making under $40,000.