| Year | Count |
|---|---|
| 1968 | 6 |
| 1972 | 9 |
| 1975 | 11 |
| 1976 | 14 |
| 1979 | 16 |
| 1982 | 11 |
| 1984 | 7 |
| 1985 | 16 |
| 1986 | 16 |
| 1987 | 45 |
| 1988 | 18 |
| 1989 | 21 |
| 1990 | 21 |
| 1991 | 28 |
| 1992 | 58 |
| 1993 | 97 |
| 1994 | 120 |
| 1995 | 136 |
| 1996 | 231 |
| 1997 | 230 |
| 1998 | 296 |
| 1999 | 359 |
| 2000 | 358 |
| 2001 | 397 |
| 2002 | 443 |
| 2003 | 556 |
| 2004 | 931 |
| 2005 | 1,070 |
| 2006 | 891 |
| 2007 | 888 |
| 2008 | 936 |
| 2009 | 838 |
| 2010 | 782 |
| 2011 | 782 |
| 2012 | 765 |
| 2013 | 642 |
| 2014 | 634 |
| 2015 | 705 |
| 2016 | 771 |
| 2017 | 939 |
| 2018 | 612 |
| 2019 | 757 |
| 2020 | 568 |
| 2021 | 634 |
| 2022 | 805 |
| 2023 | 847 |
| 2024 | 791 |