| Year | Count |
|---|---|
| 1951 | 10 |
| 1952 | 30 |
| 1953 | 16 |
| 1954 | 124 |
| 1955 | 232 |
| 1956 | 337 |
| 1957 | 482 |
| 1958 | 714 |
| 1959 | 653 |
| 1960 | 881 |
| 1961 | 1,028 |
| 1962 | 1,127 |
| 1963 | 896 |
| 1964 | 840 |
| 1965 | 841 |
| 1966 | 736 |
| 1967 | 667 |
| 1968 | 538 |
| 1969 | 435 |
| 1970 | 390 |
| 1971 | 270 |
| 1972 | 121 |
| 1973 | 136 |
| 1974 | 104 |
| 1975 | 78 |
| 1976 | 66 |
| 1977 | 60 |
| 1978 | 29 |
| 1979 | 57 |
| 1980 | 28 |
| 1981 | 7 |
| 1982 | 6 |
| 1983 | 11 |
| 1984 | 7 |
| 1985 | 18 |
| 1986 | 10 |
| 1989 | 5 |