| Year | Count |
|---|---|
| 1974 | 5 |
| 1983 | 17 |
| 1984 | 5 |
| 1985 | 23 |
| 1986 | 46 |
| 1987 | 52 |
| 1988 | 66 |
| 1989 | 45 |
| 1990 | 121 |
| 1991 | 190 |
| 1992 | 275 |
| 1993 | 287 |
| 1994 | 387 |
| 1995 | 359 |
| 1996 | 378 |
| 1997 | 386 |
| 1998 | 439 |
| 1999 | 340 |
| 2000 | 368 |
| 2001 | 417 |
| 2002 | 327 |
| 2003 | 399 |
| 2004 | 587 |
| 2005 | 548 |
| 2006 | 438 |
| 2007 | 460 |
| 2008 | 442 |
| 2009 | 257 |
| 2010 | 349 |
| 2011 | 294 |
| 2012 | 315 |
| 2013 | 278 |
| 2014 | 300 |
| 2015 | 394 |
| 2016 | 319 |
| 2017 | 287 |
| 2018 | 209 |
| 2019 | 216 |
| 2020 | 159 |
| 2021 | 142 |
| 2022 | 88 |
| 2023 | 78 |
| 2024 | 40 |