Number of Milestone HR Seasons by player

Players with most years 50+ HRs:
Ruth, McGwire and Sosa: 4
Alex Rodriguez: 3
Griffey Jr., Mays, Foxx and Kiner: 2

45+:
Ruth: 9
Bonds: 6
Killebrew, McGwire, Sosa, Griffey Jr. and A-Rod: 5
Gehrig, Mays: 4

40+:
Ruth: 11
Aaron, Bonds, Killebrew and A-Rod: 8
Griffey Jr. and Sosa: 7
McGwire, Mays, and Thome: 6

35+:
Ruth and Alex Rodriguez: 12
Aaron and Schmidt: 11
Sosa, Mays, Bonds, Palmeiro and Foxx: 10

30+:
Aaron: 15
Bonds: 14
Ruth and Schmidt: 13
A-Rod, Thome, Manny Ramirez and Foxx: 12
McGwire, Frank Robinson, Sosa, Mays, and Carlos Delgado: 11

Surprises to me: despite 50-HR season becoming commonplace from 1996-2005, only 4 players did it more than once in our juiced era.

Also, Thome and Schmidt's rankings in some of these categories.
And Carlos Delgado's appearance on the last list--that's an unheralded consistently powerful career there! He'll soon be one of the quietest additions to the 500 club.

And despite Bond's notoriety for 73 (26 more than Aaron's career high of 47), Bonds amassed 700 the same way Aaron and Ruth did: with buckets of 30-homer-on-up seasons.