| Year | Count |
|---|---|
| 1947 | 26 |
| 1948 | 5 |
| 1949 | 24 |
| 1950 | 19 |
| 1951 | 51 |
| 1952 | 46 |
| 1953 | 99 |
| 1954 | 117 |
| 1955 | 147 |
| 1956 | 286 |
| 1957 | 378 |
| 1958 | 416 |
| 1959 | 576 |
| 1960 | 806 |
| 1961 | 820 |
| 1962 | 709 |
| 1963 | 646 |
| 1964 | 638 |
| 1965 | 480 |
| 1966 | 441 |
| 1967 | 439 |
| 1968 | 369 |
| 1969 | 382 |
| 1970 | 393 |
| 1971 | 355 |
| 1972 | 242 |
| 1973 | 206 |
| 1974 | 141 |
| 1975 | 152 |
| 1976 | 73 |
| 1977 | 82 |
| 1978 | 70 |
| 1979 | 36 |
| 1980 | 43 |
| 1981 | 23 |
| 1982 | 15 |
| 1983 | 19 |
| 1984 | 7 |
| 1985 | 6 |
| 1986 | 17 |
| 1987 | 5 |
| 1988 | 8 |
| 1991 | 6 |