| Year | Count |
|---|---|
| 1971 | 5 |
| 1975 | 19 |
| 1977 | 5 |
| 1979 | 33 |
| 1980 | 88 |
| 1981 | 221 |
| 1982 | 290 |
| 1983 | 427 |
| 1984 | 460 |
| 1985 | 670 |
| 1986 | 698 |
| 1987 | 848 |
| 1988 | 1,599 |
| 1989 | 1,686 |
| 1989 | 22 |
| 1990 | 1,408 |
| 1990 | 8 |
| 1991 | 1,687 |
| 1992 | 1,382 |
| 1993 | 1,512 |
| 1994 | 1,343 |
| 1995 | 1,559 |
| 1996 | 1,383 |
| 1997 | 1,169 |
| 1998 | 1,153 |
| 1999 | 938 |
| 2000 | 858 |
| 2001 | 658 |
| 2002 | 545 |
| 2003 | 477 |
| 2004 | 549 |
| 2005 | 647 |
| 2006 | 627 |
| 2007 | 489 |
| 2008 | 318 |
| 2009 | 252 |
| 2010 | 182 |
| 2011 | 187 |
| 2012 | 131 |
| 2013 | 73 |
| 2014 | 51 |
| 2015 | 107 |
| 2016 | 91 |
| 2017 | 75 |
| 2018 | 40 |
| 2019 | 52 |
| 2020 | 64 |
| 2021 | 63 |
| 2022 | 57 |
| 2023 | 44 |
| 2024 | 47 |