Sunfish FAIP - 591 guys 37 and younger. Add in another 10-12 38 year olds younger than you and you're looking at retiring at roughly #600. Based on early retirements, quits, fired, and unfortunately deaths you'd be around #520 ish.

All those numbers will increase for anyone younger hired between today and when you show up.

Currently 1020 G4 Captains. Junior G4 Captain is 2500 ish. If you went to the junior base and upgraded to G4 CA (330/350/777/787) you be able to hold it with approx 8+ yrs to retirement.

Current G3 CA (757/767) count is 550. That will decrease to approx 300 (+/-).

G4 pay is 23% more than G2 pay.
G3 pay is 6% more than G2 pay.

For many pilots the loss of seniority going from G2 to G3 is not worth it for a 6% pay increase.

G4's additional 23% pay, plus the type of flying (330/350777/787) international long haul, is the top of the food chain so many guys take the seniority hit and bid the G4 planes.