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Wednesday, June 29, 2011
Historical roster trend
This gives you the number of pitchers and nonpitchers that were on each team for each year. I counted any nonpitcher who had as many plate appearances as there were team games (so, these days, that means at least 162 PA). For pitchers, I counted anyone with at least 0.23 innings per team game (so, these days, that means at least 37 innings).
We see that since the new run environment (1993-present), the % of roster spots allocated to pitchers is almost exactly 50%.
The jump started occurring in 1990, likely due to specialization of relievers. Prior to then, the number of relievers used topped off at 11.3 per team. From 1951-1984, the number of pitchers used hovered from 9.7 to 10.9 per team.
As for nonpitchers, it’s been holding quite steady since 1973 (DH?). Since then, we’ve had 12.5 nonpitchers per team. Prior to that, since 1922, it was 11.7 nonpitchers.
year Pitchers NonPitchers Players % Pitchers
1916 8.1 11.1 19.2 42%
1917 7.4 10.9 18.3 41%
1918 7.6 10.9 18.6 41%
1919 7.6 10.6 18.2 42%
1920 7.4 10.8 18.3 41%
1921 7.8 10.9 18.8 42%
1922 7.9 11.3 19.2 41%
1923 7.8 11.3 19.1 41%
1924 8.4 11.6 20.0 42%
1925 8.4 12.3 20.7 41%
1926 8.4 11.5 19.9 42%
1927 8.3 11.7 20.0 42%
1928 8.6 11.7 20.3 42%
1929 8.5 11.2 19.7 43%
1930 8.4 11.9 20.3 42%
1931 8.6 11.8 20.4 42%
1932 8.4 11.3 19.8 43%
1933 8.9 10.8 19.8 45%
1934 8.5 11.6 20.1 42%
1935 8.8 11.5 20.3 43%
1936 8.8 10.8 19.6 45%
1937 8.9 11.1 19.9 45%
1938 8.9 11.0 19.9 45%
1939 9.1 12.0 21.1 43%
1940 9.4 11.1 20.4 46%
1941 9.5 11.5 21.0 45%
1942 9.6 11.6 21.1 45%
1943 9.3 11.4 20.8 45%
1944 8.9 11.6 20.6 43%
1945 9.7 12.0 21.7 45%
1946 10.3 12.6 22.8 45%
1947 9.9 11.6 21.5 46%
1948 9.5 12.1 21.6 44%
1949 9.3 12.6 21.9 43%
1950 9.4 11.6 21.0 45%
1951 9.7 12.4 22.1 44%
1952 10.2 11.5 21.7 47%
1953 9.8 11.4 21.3 46%
1954 9.8 11.4 21.3 46%
1955 10.4 11.8 22.3 47%
1956 10.1 11.7 21.8 46%
1957 10.2 12.1 22.3 46%
1958 10.2 12.3 22.4 45%
1959 9.7 11.9 21.6 45%
1960 10.1 11.8 21.9 46%
1961 10.0 11.8 21.8 46%
1962 10.6 11.4 22.0 48%
1963 10.1 12.1 22.2 45%
1964 10.4 11.8 22.2 47%
1965 10.3 12.0 22.3 46%
1966 10.6 11.7 22.3 47%
1967 10.8 11.7 22.5 48%
1968 10.2 12.1 22.3 46%
1969 10.2 12.1 22.3 46%
1970 10.2 11.8 22.0 46%
1971 10.1 12.0 22.1 46%
1972 9.9 11.5 21.4 46%
1973 9.8 12.2 21.9 44%
1974 9.9 12.2 22.1 45%
1975 10.2 12.5 22.7 45%
1976 10.1 12.5 22.6 45%
1977 10.2 12.2 22.3 46%
1978 10.2 12.2 22.4 46%
1979 10.7 12.2 22.9 47%
1980 10.2 12.9 23.2 44%
1981 10.7 11.7 22.3 48%
1982 10.6 12.2 22.7 47%
1983 10.8 12.3 23.1 47%
1984 10.9 12.5 23.4 47%
1985 11.3 12.4 23.7 48%
1986 11.0 12.9 23.9 46%
1987 11.0 12.7 23.7 47%
1988 10.7 12.3 22.9 46%
1989 11.3 12.9 24.2 47%
1990 11.8 12.6 24.4 48%
1991 11.7 13.0 24.6 47%
1992 12.1 12.8 24.9 49%
1993 12.2 12.7 24.9 49%
1994 12.0 12.5 24.5 49%
1995 12.1 12.9 25.0 48%
1996 12.3 12.3 24.6 50%
1997 12.4 12.8 25.1 49%
1998 12.2 12.7 24.9 49%
1999 12.5 12.6 25.1 50%
2000 12.3 12.9 25.2 49%
2001 12.5 12.3 24.8 50%
2002 12.4 12.6 25.1 50%
2003 12.5 12.5 25.1 50%
2004 12.3 12.6 24.9 49%
2005 12.2 12.4 24.6 50%
2006 13.0 12.5 25.5 51%
2007 13.1 12.7 25.8 51%
2008 13.1 12.5 25.6 51%
2009 13.3 12.5 25.8 51%
2010 12.5 12.7 25.2 50%