I rode the graph down with a 3000ish seniority guy. This is probably pretty accurate within a +/-5.

Year- Retiring
2017-9
18-14
19-19
20-40
21-38
22-37
23-65
24-75
25-56
26-70
27-113
28-135
29-130
30-135
31-130
32-148
33-170
34-176
35-160
36.... I've lost interest