still climbing
It's literally doing the opposite, liar (and/or reposter of ancient memes), lol.
It peaked around 2008, at ~24.7%. By 2015, it had fallen to 21%. By 2020, it was 20%.
Data from 2022 indicates the share has continued to trend downwards, though apparently most countries don't report these statistics as often as the US does, and that seems to be the reason I can't find a more recent 'percent of the world's' figure. Still, given that it's been less than the 22% in the meme for at least a decade, I can confidently stand by the first thing I said here.
But, again, it's literally doing the opposite of climbing, and hasn't been climbing for ~15 years.
It's a near-worthless figure anyway—if I have 100 apples and 15 of them are rotten, and you have 5 apples which are all rotten, then I have 75% of all the rotten apples, while you only have 25%. But only 15% of mine are, while 100% of yours are. Which figure is more useful in gleaning information about how rotten person X's apples are on average?
An actually-useful figure for a country is what percentage of that country's population is incarcerated.