Strange Planet by Nathan W. Pyle

Base 12 is not organically common, it's incredibly rare even with the modern counting systems we've discovered...

The frequency of emergences (based on language families that use them) are: 4 ~1 time, 5 ~4 times, 6 ~3 times, 8 ~2 times, 10 ?? times, 12 ~3 times, 15 ~1 time, 20 ~9 times, 20+5 ~2 times, 23 ~1 time, 24 ~1 time, 27 ~1-2 times, 32 ~1 time, 60 ~2 times