⚡ TL;DR
Per UPSC's 73rd Annual Report, the 24-26 age band produces the most selections — 29.4% of selected men and 33.3% of selected women. The under-23 group accounts for under 15% of selections; the above-30 group accounts for ~13-15%. The exam is statistically a 24-28-year-old's playing field.
BharatNotes