Associations by Supporting Reference Year
| 1892 | 2 |
| 1902 | 1 |
| 1908 | 1 |
| 1911 | 3 |
| 1914 | 10 |
| 1916 | 2 |
| 1917 | 1 |
| 1918 | 3 |
| 1919 | 2 |
| 1920 | 2 |
| 1922 | 9 |
| 1926 | 3 |
| 1927 | 2 |
| 1928 | 1 |
| 1929 | 1 |
| 1930 | 5 |
| 1931 | 2 |
| 1933 | 3 |
| 1934 | 1 |
| 1935 | 5 |
| 1936 | 3 |
| 1939 | 1 |
| 1940 | 2 |
| 1944 | 1 |
| 1945 | 1 |
| 1947 | 3 |
| 1949 | 2 |
| 1951 | 1 |
| 1952 | 2 |
| 1954 | 3 |
| 1955 | 44 |
| 1957 | 7 |
| 1961 | 1 |
| 1962 | 5 |
| 1963 | 3 |
| 1964 | 13 |
| 1965 | 22 |
| 1966 | 3 |
| 1967 | 4 |
| 1968 | 4 |
| 1969 | 5 |
| 1971 | 4 |
| 1972 | 1 |
| 1973 | 3 |
| 1974 | 5 |
| 1975 | 1 |
| 1977 | 1 |
| 1978 | 12 |
| 1979 | 20 |
| 1980 | 32 |
| 1981 | 9 |
| 1982 | 3 |
| 1983 | 9 |
| 1984 | 7 |
| 1985 | 3 |
| 1986 | 1 |
| 1987 | 9 |
| 1989 | 4 |
| 1990 | 3 |
| 1991 | 15 |
| 1992 | 1 |
| 1993 | 4 |
| 1994 | 9 |
| 1996 | 2 |
| 1997 | 2 |
| 1998 | 5 |
| 1999 | 11 |
| 2000 | 17 |
| 2001 | 7 |
| 2002 | 53 |
| 2003 | 1 |
| 2004 | 4 |
| 2006 | 3 |