| Year | Count |
|---|---|
| 1972 | 5 |
| 1975 | 17 |
| 1977 | 6 |
| 1978 | 36 |
| 1979 | 10 |
| 1981 | 30 |
| 1982 | 7 |
| 1983 | 27 |
| 1984 | 29 |
| 1985 | 51 |
| 1986 | 66 |
| 1987 | 61 |
| 1988 | 132 |
| 1989 | 135 |
| 1990 | 147 |
| 1991 | 193 |
| 1992 | 298 |
| 1993 | 292 |
| 1994 | 326 |
| 1995 | 304 |
| 1996 | 415 |
| 1997 | 355 |
| 1998 | 370 |
| 1999 | 348 |
| 2000 | 403 |
| 2001 | 368 |
| 2002 | 235 |
| 2003 | 217 |
| 2004 | 245 |
| 2005 | 183 |
| 2006 | 198 |
| 2007 | 164 |
| 2008 | 157 |
| 2009 | 128 |
| 2010 | 87 |
| 2011 | 138 |
| 2012 | 85 |
| 2013 | 70 |
| 2014 | 70 |
| 2015 | 71 |
| 2016 | 63 |
| 2017 | 106 |
| 2018 | 40 |
| 2019 | 37 |
| 2020 | 56 |
| 2021 | 60 |
| 2022 | 26 |
| 2023 | 29 |
| 2024 | 24 |