Here is an interesting rundown on league leading IP pitchers.
300+, 275+, 250+, 225+, 200+
1920: 10, 18, 35, 56
1930: 0, 6, 14, 39
1940: 2, 8, 25, 31
1950: 2, 6, 26, 39
1960: 0, 3, 14, 33
1970: 4, 11, 27, 56
1980: 1, 7, 17, 56
1990: 0, 1, 17, 42
2000: 0, 1, 13, 37
2010: 0, 1, 7, 45
2022: 0, 0, 1, 8