| Year | Value | | 2024 | 498 | | 2023 | 483 | | 2022 | 477 | | 2021 | 476 | | 2020 | 468 | | 2019 | 458 | | 2018 | 436 | | 2017 | 405 | | 2016 | 368 | | 2015 | 331 | | 2014 | 312 | | 2013 | 315 | | 2012 | 312 | | 2011 | 295 | | 2010 | 286 | | 2009 | 286 | | 2008 | 284 | | 2007 | 276 | | 2006 | 264 | | 2005 | 246 | | 2004 | 229 | | 2003 | 216 | | 2002 | 204 | | 2001 | 189 | | 2000 | 173 | | 1999 | 159 | | 1998 | 147 | | 1997 | 139 | | 1996 | 138 | | 1995 | 142 | | 1994 | 145 | | 1993 | 148 | | 1992 | 150 | | 1991 | 152 | | 1990 | 152 | | 1989 | 150 | | 1988 | 148 | | 1987 | 141 | | 1986 | 134 | | 1985 | 128 | | 1984 | 128 | | 1983 | 132 | | 1982 | 133 | | 1981 | 131 | | 1980 | 125 | | 1979 | 120 | | 1978 | 117 | | 1977 | 116 | | 1976 | 114 | | 1975 | 110 |
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