If you just look up “most common fetishes” foot fetishes are commonly near the top of the list, and are almost always the most popular part of the body for body parts that aren’t sexually dimorphic. https://bedbible.com/what-is-the-most-common-fetish-statistics/ here’s a random website study I pulled, but if you search it up it’s common across more than one study.

You’re “technically” correct in that most people don’t identify as having a fetish at all, so the percentage of literally any fetish is a small percent of people. But when you talk about the most common fetishes, you’re only talking about the population of people who have fetishes in the first place.