extrapolated from a survey on 1000 americans over 18
"The survey was conducted by the Innovation Center of US Dairy in April. 1,000 adults 18 and over were asked questions about the role milk plays in their daily lives, Food & Wine reported.
The study found 48% of respondents weren't sure where chocolate milk came from. Seven percent thought chocolate milk only comes from brown cows."
https://www.nbc4i.com/news/u-s-world/study-finds-surprising-number-of-americans-think-chocolate-milk-comes-from-brown-cows/1064794299