| Year | Count |
|---|---|
| 1921 | 5 |
| 1923 | 6 |
| 1925 | 6 |
| 1929 | 5 |
| 1930 | 7 |
| 1933 | 5 |
| 1935 | 7 |
| 1938 | 8 |
| 1940 | 5 |
| 1942 | 5 |
| 1945 | 7 |
| 1947 | 20 |
| 1948 | 6 |
| 1950 | 7 |
| 1951 | 13 |
| 1952 | 6 |
| 1953 | 13 |
| 1954 | 17 |
| 1955 | 45 |
| 1956 | 212 |
| 1957 | 80 |
| 1958 | 108 |
| 1959 | 148 |
| 1960 | 146 |
| 1961 | 98 |
| 1962 | 91 |
| 1963 | 149 |
| 1964 | 240 |
| 1965 | 160 |
| 1966 | 210 |
| 1967 | 142 |
| 1968 | 166 |
| 1969 | 165 |
| 1970 | 153 |
| 1971 | 122 |
| 1972 | 80 |
| 1973 | 39 |
| 1974 | 48 |
| 1975 | 49 |
| 1976 | 13 |
| 1977 | 10 |
| 1978 | 5 |
| 1979 | 23 |
| 1980 | 49 |
| 1981 | 16 |
| 1982 | 24 |
| 1983 | 5 |
| 1984 | 5 |
| 1987 | 10 |
| 1988 | 5 |
| 1991 | 12 |
| 1997 | 5 |