| Year | Count |
|---|---|
| 1978 | 5 |
| 1981 | 8 |
| 1982 | 10 |
| 1983 | 14 |
| 1984 | 18 |
| 1985 | 22 |
| 1986 | 27 |
| 1987 | 48 |
| 1988 | 65 |
| 1989 | 106 |
| 1990 | 180 |
| 1991 | 283 |
| 1992 | 360 |
| 1993 | 577 |
| 1994 | 839 |
| 1995 | 808 |
| 1996 | 673 |
| 1997 | 727 |
| 1998 | 543 |
| 1999 | 496 |
| 2000 | 477 |
| 2001 | 464 |
| 2002 | 363 |
| 2003 | 298 |
| 2004 | 291 |
| 2005 | 205 |
| 2006 | 189 |
| 2007 | 160 |
| 2008 | 139 |
| 2009 | 112 |
| 2010 | 63 |
| 2011 | 72 |
| 2012 | 33 |
| 2013 | 63 |
| 2014 | 63 |
| 2015 | 40 |
| 2016 | 53 |
| 2017 | 33 |
| 2018 | 55 |
| 2019 | 23 |
| 2020 | 15 |
| 2021 | 24 |
| 2022 | 22 |
| 2024 | 12 |