I think GenX are just about to become the largest Cohort, but only for about ten years.

EDIT.

I've just done some online research. As of the most recent US Presidential election, the Baby Boomers were still the largest Cohort at about 28% of the vote. They are aging out rapidly, with many being to frail to vote.

The next elections (midterms) will probably be the first election in which they are not the largest cohort, with GenX making up about 20-25% of the vote. So this is very current, it is happening pretty much as we speak.

I think GenX are just about to become the largest Cohort, but only for about ten years.