| Year | Value | | 2024 | 437 | | 2023 | 425 | | 2022 | 414 | | 2021 | 404 | | 2020 | 388 | | 2019 | 364 | | 2018 | 344 | | 2017 | 322 | | 2016 | 298 | | 2015 | 281 | | 2014 | 275 | | 2013 | 276 | | 2012 | 274 | | 2011 | 260 | | 2010 | 243 | | 2009 | 236 | | 2008 | 231 | | 2007 | 225 | | 2006 | 223 | | 2005 | 216 | | 2004 | 202 | | 2003 | 185 | | 2002 | 163 | | 2001 | 145 | | 2000 | 141 | | 1999 | 147 | | 1998 | 157 | | 1997 | 167 | | 1996 | 177 | | 1995 | 186 | | 1994 | 184 | | 1993 | 182 | | 1992 | 185 | | 1991 | 182 | | 1990 | 174 | | 1989 | 168 | | 1988 | 159 | | 1987 | 148 | | 1986 | 146 | | 1985 | 146 | | 1984 | 141 | | 1983 | 142 | | 1982 | 150 | | 1981 | 157 | | 1980 | 156 | | 1979 | 150 | | 1978 | 134 | | 1977 | 117 | | 1976 | 108 | | 1975 | 107 |
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