| Year | Count |
|---|---|
| 1974 | 5 |
| 1978 | 7 |
| 1979 | 36 |
| 1980 | 10 |
| 1981 | 41 |
| 1982 | 67 |
| 1983 | 69 |
| 1984 | 61 |
| 1985 | 92 |
| 1986 | 108 |
| 1987 | 97 |
| 1988 | 159 |
| 1989 | 278 |
| 1990 | 274 |
| 1991 | 427 |
| 1992 | 491 |
| 1993 | 544 |
| 1994 | 572 |
| 1995 | 559 |
| 1996 | 531 |
| 1997 | 474 |
| 1998 | 452 |
| 1999 | 410 |
| 2000 | 385 |
| 2001 | 366 |
| 2002 | 243 |
| 2003 | 190 |
| 2004 | 174 |
| 2005 | 179 |
| 2006 | 139 |
| 2007 | 165 |
| 2008 | 154 |
| 2009 | 93 |
| 2010 | 101 |
| 2011 | 90 |
| 2012 | 82 |
| 2013 | 56 |
| 2014 | 76 |
| 2015 | 54 |
| 2016 | 39 |
| 2017 | 34 |
| 2018 | 60 |
| 2019 | 63 |
| 2020 | 69 |
| 2021 | 47 |
| 2022 | 45 |
| 2023 | 26 |
| 2024 | 27 |