50-Double Seasons by Decade

Here is the breakdown of the number of 50-double seasons in each decade of the history of the majors:
1880s: 1
1890s: 2
1900s: 0
1910s: 2
1920s: 12
1930s: 20
1940s: 5
1950s: 2
1960s: 1
1970s: 2
1980s: 2
1990s: 10
2000s: 27 so far

Thus there have been more 50 double seasons this decade than in the previous 6 decades combined.

A similar pattern is found in the rarer 50-homer season stats. Here is the decade breakdown for that:
1920s: 4
1930s: 4
1940s: 3
1950s: 2
1960s: 3
1970s: 1
1980s: 0
1990s: 12
2000s: 12 so far