| Year | Count |
|---|---|
| 1963 | 6 |
| 1966 | 34 |
| 1967 | 19 |
| 1968 | 126 |
| 1969 | 94 |
| 1970 | 140 |
| 1971 | 236 |
| 1972 | 249 |
| 1973 | 213 |
| 1974 | 244 |
| 1975 | 262 |
| 1976 | 301 |
| 1977 | 270 |
| 1978 | 250 |
| 1979 | 249 |
| 1980 | 321 |
| 1981 | 279 |
| 1982 | 329 |
| 1983 | 401 |
| 1984 | 382 |
| 1985 | 583 |
| 1986 | 480 |
| 1987 | 728 |
| 1988 | 647 |
| 1989 | 709 |
| 1990 | 773 |
| 1991 | 806 |
| 1992 | 682 |
| 1993 | 620 |
| 1994 | 591 |
| 1995 | 517 |
| 1996 | 502 |
| 1997 | 404 |
| 1998 | 320 |
| 1999 | 209 |
| 2000 | 187 |
| 2001 | 189 |
| 2002 | 82 |
| 2003 | 74 |
| 2004 | 87 |
| 2005 | 61 |
| 2006 | 43 |
| 2007 | 16 |
| 2008 | 27 |
| 2009 | 14 |
| 2010 | 55 |
| 2011 | 8 |
| 2012 | 10 |
| 2014 | 5 |
| 2016 | 5 |