| Year | Count |
|---|---|
| 1953 | 7 |
| 1955 | 24 |
| 1956 | 27 |
| 1957 | 23 |
| 1958 | 61 |
| 1959 | 74 |
| 1960 | 127 |
| 1961 | 104 |
| 1962 | 106 |
| 1963 | 106 |
| 1964 | 173 |
| 1965 | 186 |
| 1966 | 185 |
| 1967 | 209 |
| 1968 | 328 |
| 1969 | 338 |
| 1970 | 481 |
| 1971 | 561 |
| 1972 | 574 |
| 1973 | 546 |
| 1974 | 585 |
| 1975 | 619 |
| 1976 | 519 |
| 1977 | 540 |
| 1978 | 514 |
| 1979 | 482 |
| 1980 | 461 |
| 1981 | 362 |
| 1982 | 228 |
| 1983 | 211 |
| 1984 | 152 |
| 1985 | 158 |
| 1986 | 125 |
| 1987 | 87 |
| 1988 | 70 |
| 1989 | 46 |
| 1990 | 45 |
| 1991 | 37 |
| 1992 | 31 |
| 1993 | 15 |
| 1994 | 12 |
| 1995 | 10 |
| 1996 | 5 |
| 1997 | 6 |