| Year | Count |
|---|---|
| 1972 | 6 |
| 1974 | 5 |
| 1975 | 19 |
| 1976 | 12 |
| 1978 | 5 |
| 1980 | 20 |
| 1981 | 32 |
| 1984 | 5 |
| 1986 | 5 |
| 1987 | 6 |
| 1988 | 17 |
| 1989 | 15 |
| 1991 | 5 |
| 1992 | 5 |
| 1993 | 7 |
| 1995 | 15 |
| 1996 | 601 |
| 1997 | 710 |
| 1998 | 1,023 |
| 1999 | 784 |
| 2000 | 745 |
| 2001 | 983 |
| 2002 | 612 |
| 2003 | 744 |
| 2004 | 1,196 |
| 2005 | 852 |
| 2006 | 675 |
| 2007 | 793 |
| 2008 | 733 |
| 2009 | 450 |
| 2010 | 389 |
| 2011 | 340 |
| 2012 | 374 |
| 2013 | 336 |
| 2014 | 269 |
| 2015 | 308 |
| 2016 | 286 |
| 2017 | 279 |
| 2018 | 133 |
| 2019 | 129 |
| 2020 | 104 |
| 2021 | 94 |
| 2022 | 95 |
| 2023 | 30 |
| 2024 | 27 |