1. If you believe that being gay is largely genetic
2. do you believe that some countries have just more gay genes?
3. if not you can assume that the highest gay ratio in countries is more representative than the lower ones of specific countries.
4. If you look at https://en.wikipedia.org/wiki/Demographics_of_sexual_orientation there are some countries with >=7%

I think the largest reason for lower reports is social pressure and the flexibility applied when being unhappy with your own orientation due to that pressure “I am not gay. I just like to experiment!” I believe that this partly causes the relatively large amount of “not completely straight” people in more precise studies.

Anyway, this is a lot of guess work. Mainly I had this presumption, because a gay man I know stated “I can ask 10 men on the street and one will join me” and given that it sounded like he tried it a few times, I do believe him. So my starting position is highly anecdotal and not very scientific.