According to this article, 5-6% of the public (the American public, I presume) still believe that the moon landing never happened, it was a clever hoax perpetrated by some evil villains. Many of these same people are flat earth theorists. The earth is a stationary disc, central to everything, and the sun and the moon are just lights circling around. Here's the article:
https://tinyurl.com/y42dwno7
https://tinyurl.com/y42dwno7