University of Michigan did a recent study that shows intentional childfree cohort at at least around 20% in Michigan [1]. Would be super interesting to expand these studies out across wider populations.

Somewhat related, about 40-50% annually of both US [2] and global [3] pregnancies are unintended. How many are unintended and unwanted would also be an interesting datapoint. This would provide signal as to folks who perhaps wanted to remain childfree but didn't because of circumstances.

[1] https://www.michiganradio.org/health/2022-07-27/1-in-5-adult...

[2] https://www.guttmacher.org/fact-sheet/unintended-pregnancy-u...

[3] https://www.unfpa.org/press/nearly-half-all-pregnancies-are-...