| Year | Count |
|---|---|
| 1950 | 15 |
| 1954 | 5 |
| 1956 | 19 |
| 1957 | 47 |
| 1958 | 45 |
| 1960 | 12 |
| 1961 | 12 |
| 1962 | 16 |
| 1963 | 24 |
| 1964 | 53 |
| 1965 | 49 |
| 1966 | 72 |
| 1967 | 81 |
| 1968 | 79 |
| 1969 | 102 |
| 1970 | 71 |
| 1971 | 108 |
| 1972 | 252 |
| 1973 | 294 |
| 1974 | 274 |
| 1975 | 297 |
| 1976 | 261 |
| 1977 | 277 |
| 1978 | 237 |
| 1979 | 285 |
| 1980 | 238 |
| 1981 | 185 |
| 1982 | 230 |
| 1983 | 223 |
| 1984 | 247 |
| 1985 | 573 |
| 1986 | 492 |
| 1987 | 363 |
| 1988 | 267 |
| 1989 | 252 |
| 1989 | 6 |
| 1990 | 202 |
| 1991 | 334 |
| 1992 | 176 |
| 1993 | 108 |
| 1994 | 32 |
| 1995 | 23 |
| 1997 | 10 |
| 1998 | 10 |