| Year | Count |
|---|---|
| 1970 | 28 |
| 1971 | 54 |
| 1972 | 44 |
| 1973 | 72 |
| 1974 | 55 |
| 1975 | 42 |
| 1976 | 54 |
| 1977 | 24 |
| 1978 | 17 |
| 1979 | 20 |
| 1980 | 12 |
| 1982 | 12 |
| 1983 | 12 |
| 1986 | 5 |
| 1991 | 8 |
| 1992 | 11 |
| 1993 | 6 |
| 1994 | 12 |
| 1995 | 11 |
| 1996 | 10 |
| 1997 | 19 |
| 1998 | 5 |
| 1999 | 35 |
| 2000 | 29 |
| 2001 | 61 |
| 2002 | 39 |
| 2003 | 26 |
| 2004 | 70 |
| 2005 | 103 |
| 2006 | 106 |
| 2007 | 150 |
| 2008 | 246 |
| 2009 | 265 |
| 2010 | 270 |
| 2011 | 286 |
| 2012 | 380 |
| 2013 | 419 |
| 2014 | 483 |
| 2015 | 607 |
| 2016 | 745 |
| 2017 | 774 |
| 2018 | 810 |
| 2019 | 904 |
| 2020 | 668 |
| 2021 | 810 |
| 2022 | 762 |
| 2023 | 529 |
| 2024 | 477 |