https://www.quora.com/What-percentage-of-pre-med-students-eventually-become-doctors
With respect to Doyen Rainey, only about 17% of US Freshman pre meds earn admission to med school. About 140,000 start out. Half drop the program before completion. Of those who “stick it out” and take the MCAT (~70,000), half do not do well enough on the MCAT even to apply. Of the ~ 35,000 who apply, a little under half get in. Among the ~18,000–20,000 applicants who are rejected (and some of those who didn’t apply after their first MCAT), about 6,000 will eventually earn admission on subsequent attempts.