| Year | Count |
|---|---|
| 1958 | 14 |
| 1962 | 11 |
| 1963 | 5 |
| 1964 | 36 |
| 1965 | 49 |
| 1966 | 56 |
| 1967 | 73 |
| 1968 | 155 |
| 1969 | 216 |
| 1970 | 300 |
| 1971 | 313 |
| 1972 | 379 |
| 1973 | 460 |
| 1974 | 348 |
| 1975 | 382 |
| 1976 | 320 |
| 1977 | 272 |
| 1978 | 294 |
| 1979 | 463 |
| 1980 | 490 |
| 1981 | 474 |
| 1982 | 401 |
| 1983 | 256 |
| 1984 | 280 |
| 1985 | 341 |
| 1986 | 255 |
| 1987 | 183 |
| 1988 | 237 |
| 1989 | 215 |
| 1990 | 178 |
| 1991 | 141 |
| 1992 | 171 |
| 1993 | 109 |
| 1994 | 32 |
| 1995 | 62 |
| 1996 | 87 |
| 1997 | 26 |
| 1998 | 77 |
| 1999 | 23 |
| 2000 | 44 |
| 2001 | 43 |
| 2002 | 12 |
| 2003 | 18 |
| 2004 | 54 |
| 2005 | 88 |
| 2006 | 6 |
| 2010 | 5 |