i think "half the people" is an overestimate. i don't think most people learn integration in school. i'd be surprised if half learn differential calculus.
This is probably pretty country specific, I just looked up which proportion of people in Germany reaches the qualification to enter university, about 50%, and calculus is mandatory on that way, differential and integral. But I ignored that this proportion increased over time, it was only 22% in 1980. So let's call it a quarter of the population or make the differentiate or explain something about plate tectonics.