| Year | Count |
|---|---|
| 1971 | 5 |
| 1976 | 6 |
| 1977 | 5 |
| 1978 | 55 |
| 1979 | 87 |
| 1980 | 64 |
| 1981 | 63 |
| 1982 | 61 |
| 1983 | 79 |
| 1984 | 101 |
| 1985 | 134 |
| 1986 | 121 |
| 1987 | 143 |
| 1988 | 192 |
| 1989 | 254 |
| 1990 | 347 |
| 1991 | 348 |
| 1992 | 427 |
| 1993 | 392 |
| 1994 | 435 |
| 1995 | 448 |
| 1996 | 611 |
| 1997 | 690 |
| 1998 | 1,036 |
| 1999 | 902 |
| 2000 | 741 |
| 2001 | 807 |
| 2002 | 771 |
| 2003 | 789 |
| 2004 | 1,079 |
| 2005 | 943 |
| 2006 | 835 |
| 2007 | 747 |
| 2008 | 644 |
| 2009 | 625 |
| 2010 | 571 |
| 2011 | 512 |
| 2012 | 594 |
| 2013 | 516 |
| 2014 | 476 |
| 2015 | 533 |
| 2016 | 562 |
| 2017 | 477 |
| 2018 | 506 |
| 2019 | 453 |
| 2020 | 360 |
| 2021 | 535 |
| 2022 | 458 |
| 2023 | 344 |
| 2024 | 329 |