| 1965 | 1 |
| 1966 | 1 |
| 1967 | 10 |
| 1968 | 14 |
| 1969 | 23 |
| 1970 | 20 |
| 1971 | 23 |
| 1972 | 35 |
| 1973 | 51 |
| 1974 | 58 |
| 1975 | 77 |
| 1976 | 74 |
| 1977 | 80 |
| 1978 | 92 |
| 1979 | 105 |
| 1980 | 117 |
| 1981 | 128 |
| 1982 | 130 |
| 1983 | 144 |
| 1984 | 169 |
| 1985 | 194 |
| 1986 | 203 |
| 1987 | 156 |
| 1988 | 211 |
| 1989 | 216 |
| 1990 | 154 |
| 1991 | 170 |
| 1992 | 202 |
| 1993 | 161 |
| 1994 | 208 |
| 1995 | 214 |
| 1996 | 188 |
| 1997 | 187 |
| 1998 | 340 |
| 1999 | 327 |
| 2000 | 343 |
| 2001 | 398 |
| 2002 | 355 |
| 2003 | 460 |
| 2004 | 485 |
| 2005 | 458 |
| 2006 | 538 |
| 2007 | 658 |
| 2008 | 503 |
| 2009 | 471 |
| 2010 | 500 |
| 2011 | 508 |
| 2012 | 463 |
| 2013 | 586 |
| 2014 | 607 |
| 2015 | 590 |
| 2016 | 577 |
| 2017 | 491 |
| 2018 | 482 |
| 2019 | 576 |
| 2020 | 504 |
| 2021 | 539 |
| 2022 | 631 |
| 2023 | 554 |
| 2024 | 442 |
| 2025 | 340 |
| 2026 | 10 |
| not yet published | 3 |