It's buried in one of the NRMP fellowship statistics. People matching endocrine in 2019:
1st choice: 43%
2nd choice: 14.9%
3rd choice: 8.5%
Greater than 3rd: 17.9%
Matched other specialty: 1.7%
So to match your top 3 you have a 66.4% chance based off last year!
Just want to update the stats. The original numbers above are based off the total applicants in endo (meaning including ppl who had endo NOT as their preferred specialty) and who went unmatched.
If you used the total # of ppl who matched endo AND matched their preferred specialty then the numbers are:
1st choice: 52%
2nd choice: 18%
3rd choice: 10.3%
So seems like 80.3% of people should match somewhere in their top 3?