| Year | Count |
|---|---|
| 1953 | 5 |
| 1955 | 14 |
| 1956 | 12 |
| 1958 | 5 |
| 1961 | 18 |
| 1962 | 10 |
| 1965 | 11 |
| 1967 | 5 |
| 1970 | 10 |
| 1971 | 21 |
| 1976 | 6 |
| 1977 | 19 |
| 1978 | 18 |
| 1979 | 5 |
| 1980 | 7 |
| 1981 | 9 |
| 1982 | 200 |
| 1983 | 321 |
| 1984 | 150 |
| 1985 | 204 |
| 1986 | 307 |
| 1987 | 467 |
| 1988 | 585 |
| 1989 | 634 |
| 1990 | 498 |
| 1991 | 570 |
| 1992 | 437 |
| 1993 | 421 |
| 1994 | 372 |
| 1995 | 345 |
| 1996 | 238 |
| 1997 | 233 |
| 1998 | 201 |
| 1999 | 159 |
| 2000 | 136 |
| 2001 | 106 |
| 2002 | 90 |
| 2003 | 17 |
| 2004 | 38 |
| 2005 | 10 |
| 2006 | 12 |
| 2007 | 7 |