Skating clubs. Those who skate in competitions but not on the Olympic/Nationals levels
I can answer about my area of the US.
"Competitive skaters" in the US could be defined as those who enter qualifying competitions -- Regionals at Juvenile, Intermediate, Novice, Junior, and Senior levels, aiming to qualify for Sectionals and Nationals. (Plus the few who have byes)
Juveniles are not allowed to do triples.
My region is one of the larger, more competitive regions in the country, but with few major training centers. So you can consider the percentage of triples landed a bit above average.
At regionals last year there were 76 intermediate ladies competing (not counting a handful of withdrawals) in 5 initial rounds, with top 4 from each group moving onto the final round short and long program. From a quick skim of the protocols, it looks like 4 of those skaters landed at least one triple in at least one program and 1 or 2 others attempted but did not succeed.
Of 7 intermediate men, 2 landed triples.
There were 55 novice ladies in 4 groups, of whom 9 landed clean or moderately flawed triples in the initial rounds and moved on to the finals, and 2 others attempted but failed and didn't move on.
There was no novice men's event held; evidently fewer than 4 registered so they had the option to advance automatically to sectionals without competing.
There were 22 Junior ladies, of whom 9 landed at least one clean or slightly flawed triple in the freeskate and 2 others attempted but failed.
There were 2 Junior men, both of whom landed some triples.
Sixteen Senior ladies, of whom about 5 landed triples and about 5 others attempted in at least one program (they're required to attempt them in the SP, so failed attempts there don't necessarily mean that they're actually capable of landing them).
No senior men competed.
I.e., at the middle levels where triples are allowed (intermediate and novice), they are rare among the girls, less so among the boys, but there aren't nearly as many boys out there.
At junior and senior levels, in my region it seems a little less than half of the ladies have actually mastered one or more kinds of triples. Again, there are few men, but I think it's fair to say that men who compete at junior and senior levels can do some triples -- if they get to that level and can't do the jumps, they don't compete.
Skaters who actually qualify for Nationals at junior or senior level generally have several triples. It's rare for novices to make it to US Nationals (12 out of a couple hundred novice ladies in the US) without at least one or two triples, often four or five. Some but not all intermediates who make it that far include a triple or two, maybe more for the top boys.
I don't really know what the percentages are like in other countries. But skaters who get sent to international competitions usually have triples. And now that there are minimum scores required to enter ISU championships, it's nearly impossible to meet those minimums without some triples. Nor is it possible to get invited to the Grand Prix without them.
In the lower ranks of JGP and some senior B events you will see some skaters who don't attempt triples and others who attempt but can't rotate them.
Just saying, use both of your hand to draw the same figure, even if you were ambidextrous, the image drawn by the left hand will look a little different from the one by your right hand. And I am saying this from my own experience. Still, jumping in 2 directions is very impressive, though.
