As of October 24, the statistics for the Priestly Fraternity of Saint Peter have been updated.
Here is some of the information provided in the link:
Total: 421 (incl. 257 incardinated)
• Priests: 262
o 243 incardinated
o 11 incorporated ad annum
o 4 associated
o 4 postulants
• Deacons: 14
• Non-deacons seminarians (including postulants): 145
• Average age of members: 37 years
• Deceased members: 8
So the FSSP now has 262 priests, and the average age is 37. That the age of priests in traditional societies is young is pretty much the same in all traditional societies. I will post links to other traditional religious groups (SSPX, ICKSP, etc) as I get them.
One thing is clear – the traditional movement is growing, gaining strength.