My view is that, any sort of sexual partner count data, at least in the US, will always show inaccurate results, due to social factors and stigma at play. They effect people in both genders, from virgins to N-count's through the roof. I will go through each one.

Virgin to Low count Males: Males are often mocked and criticized for being a virgin and having a lack of sexual experience. I don't agree with all aspects of toxic masculinity, but one part feminists have right is the connection our culture makes between being a real man and having sex with lots of women. More so, evening outings such as clubbing or bar hopping for guys are normally deemed successful only if they find a girl to hook up with. I experienced this a lot myself, feeling lonely, shitty, and depressed that no girl at a bar was interested in me.

This results in virgin or low count males lying about their partner count, or making it higher than it actually is to fit in socially or make themselves feel better. I remember I used to flat out say my N-count was 24 when I had only slept with 2 girls before.

High-Count Males On the flip side, high count males, as in in the 30, 40 or even higher range, are likely not to reveal their true partner count. This can happen because some surveys only have an option like 25+ partners, so the really promiscuous guys get thrown in with the guys who like to lie about it like me.

Additionally, woman are usually put off by high partner count men for relationships, so such a man will most likely turn his count down and not reveal what it really is.

High Count Females Due to a combination of slut shaming, or just an internal sense of sexual privacy, high partner count girls, or even mid count girls don't really share most of their experiences. A lot of girls won't count certain sexual experiences like having sex with an exotic guy they met on vacation because they feel bad about expressing their sexuality or feel guilty of having a higher N-count. Therefore, in social circles or surveys, girls will lie that their count is lower than it actually is for improved self-esteem and social recognition.

Virgin females: On the flip side, due to today's hookup culture and more and more girls looking for studs, or like guys from the gym to have sex with, being a complete virgin as a girl is likely a target for jokes or shamming. A girl who is a complete virgin will say her partner count is 2-4 to avoid her friends bugging her about it.

tl:dr: Men exaggerate their partner count through the roof, women tone it way down, don't trust any supposed data about this stuff.