| Year | Count |
|---|---|
| 1965 | 14 |
| 1970 | 24 |
| 1973 | 18 |
| 1974 | 32 |
| 1975 | 14 |
| 1976 | 10 |
| 1977 | 34 |
| 1978 | 30 |
| 1979 | 28 |
| 1980 | 47 |
| 1981 | 55 |
| 1982 | 40 |
| 1983 | 41 |
| 1984 | 28 |
| 1985 | 63 |
| 1986 | 52 |
| 1987 | 98 |
| 1988 | 91 |
| 1989 | 145 |
| 1990 | 129 |
| 1991 | 262 |
| 1992 | 132 |
| 1993 | 153 |
| 1994 | 188 |
| 1995 | 165 |
| 1996 | 194 |
| 1997 | 246 |
| 1998 | 617 |
| 1999 | 269 |
| 2000 | 292 |
| 2001 | 347 |
| 2002 | 397 |
| 2003 | 438 |
| 2004 | 640 |
| 2005 | 712 |
| 2006 | 627 |
| 2007 | 633 |
| 2008 | 622 |
| 2009 | 621 |
| 2010 | 649 |
| 2011 | 638 |
| 2012 | 524 |
| 2013 | 572 |
| 2014 | 630 |
| 2015 | 629 |
| 2016 | 501 |
| 2017 | 471 |
| 2018 | 385 |
| 2019 | 295 |
| 2020 | 312 |
| 2021 | 305 |
| 2022 | 295 |
| 2023 | 288 |
| 2024 | 219 |