Great topic. As one of the older gents here, with a lifetime of tickling experience and a mind for analysis, I'd say it's around the following, IMHO:
Cat A: 50% - not ticklish at all
Cat B: 30% - Situationally ticklish, ranging from 4 to 7 on a 10 point scale of ticklishness
Cat C: 15% - very/extremely ticklish
Cat D: 5% - furthest end of the spectrum, beautifully, deliciously and hysterically ticklish
The best is when you come across those who sit in the ven diagram overlap of Category D who are
also in the top 5% on the beauty/hotness scale. I've been lucky enough to discover a grand total of about 5 women in this category, in the real world I mean. Out of thousands. And it is a sight/sound/experience to behold.
As for the second point, before I met my wife, I always said that my eventual spouse needs at least needs to
not be in category A, i.e. not ticklish at all. She's thankfully somewhere in between B & C, which is good enough for me, considering all of the other awesome qualities as a human being she's brought to the table.
Anyone wonders what the ticklishness of the general population is like?
If I take random samples of a hundred men and a hundred women, approximately how many would be moderately ticklish (enough to giggle and pull away) in at least one part of their body?
Also, any one of y'all worry whether the guys (or gals) you fall for will not be ticklish?