| Year | Count |
|---|---|
| 1968 | 6 |
| 1970 | 5 |
| 1972 | 9 |
| 1975 | 17 |
| 1976 | 26 |
| 1977 | 31 |
| 1978 | 40 |
| 1979 | 42 |
| 1980 | 59 |
| 1981 | 16 |
| 1982 | 46 |
| 1983 | 44 |
| 1984 | 53 |
| 1985 | 45 |
| 1986 | 59 |
| 1987 | 58 |
| 1988 | 60 |
| 1989 | 76 |
| 1990 | 88 |
| 1991 | 107 |
| 1992 | 278 |
| 1993 | 284 |
| 1994 | 367 |
| 1995 | 1,388 |
| 1996 | 842 |
| 1997 | 663 |
| 1998 | 725 |
| 1999 | 881 |
| 2000 | 721 |
| 2001 | 687 |
| 2002 | 756 |
| 2003 | 640 |
| 2004 | 768 |
| 2005 | 635 |
| 2006 | 733 |
| 2007 | 536 |
| 2008 | 659 |
| 2009 | 631 |
| 2010 | 594 |
| 2011 | 644 |
| 2012 | 767 |
| 2013 | 657 |
| 2014 | 782 |
| 2015 | 868 |
| 2016 | 901 |
| 2017 | 958 |
| 2018 | 1,093 |
| 2019 | 1,525 |
| 2020 | 1,445 |
| 2021 | 1,432 |
| 2022 | 1,320 |
| 2023 | 1,140 |
| 2024 | 955 |