| Year | Count |
|---|---|
| 1974 | 6 |
| 1975 | 11 |
| 1976 | 12 |
| 1977 | 57 |
| 1978 | 38 |
| 1979 | 29 |
| 1980 | 10 |
| 1981 | 51 |
| 1982 | 57 |
| 1983 | 56 |
| 1984 | 32 |
| 1985 | 90 |
| 1986 | 67 |
| 1987 | 51 |
| 1988 | 54 |
| 1989 | 75 |
| 1990 | 118 |
| 1991 | 76 |
| 1992 | 76 |
| 1993 | 108 |
| 1994 | 144 |
| 1995 | 160 |
| 1996 | 159 |
| 1997 | 209 |
| 1998 | 173 |
| 1999 | 184 |
| 2000 | 262 |
| 2001 | 237 |
| 2002 | 164 |
| 2003 | 224 |
| 2004 | 306 |
| 2005 | 235 |
| 2006 | 274 |
| 2007 | 215 |
| 2008 | 308 |
| 2009 | 303 |
| 2010 | 324 |
| 2011 | 366 |
| 2012 | 387 |
| 2013 | 347 |
| 2014 | 357 |
| 2015 | 488 |
| 2016 | 471 |
| 2017 | 525 |
| 2018 | 379 |
| 2019 | 552 |
| 2020 | 483 |
| 2021 | 541 |
| 2022 | 489 |
| 2023 | 573 |
| 2024 | 517 |