The first reasonable statistic that I could find was 1%, for the percentage of individuals in a large organization that used password managers [0]. Or maybe it's 8%, in a survey [1]. That 1% figure is pretty old, and people lie in surveys, so it's possibly >1% and <8%.

The vast majority of people don't use password managers (or 2FA).

[0] https://www.internetsociety.org/sites/default/files/08%20why...

[1] https://www.passwordboss.com/news/survey-finds-vast-majority...