| Year | Count |
|---|---|
| 1980 | 6 |
| 1981 | 5 |
| 1983 | 6 |
| 1984 | 12 |
| 1986 | 10 |
| 1987 | 13 |
| 1988 | 43 |
| 1989 | 156 |
| 1990 | 239 |
| 1991 | 228 |
| 1992 | 395 |
| 1993 | 855 |
| 1994 | 1,755 |
| 1995 | 2,150 |
| 1996 | 2,934 |
| 1997 | 4,094 |
| 1998 | 5,790 |
| 1999 | 5,500 |
| 2000 | 5,893 |
| 2001 | 5,922 |
| 2002 | 5,955 |
| 2003 | 5,895 |
| 2004 | 7,800 |
| 2004 | 40 |
| 2005 | 7,750 |
| 2006 | 7,523 |
| 2007 | 7,249 |
| 2008 | 7,289 |
| 2009 | 5,831 |
| 2010 | 5,953 |
| 2011 | 5,492 |
| 2012 | 4,437 |
| 2013 | 3,533 |
| 2014 | 2,750 |
| 2015 | 2,606 |
| 2016 | 2,405 |
| 2017 | 1,817 |
| 2018 | 1,588 |
| 2019 | 1,372 |
| 2020 | 949 |
| 2021 | 1,018 |
| 2022 | 946 |
| 2023 | 781 |
| 2024 | 592 |