| Year | Value | | 2022 | 1,280 | | 2021 | 1,272 | | 2020 | 1,252 | | 2019 | 1,219 | | 2018 | 1,191 | | 2017 | 1,170 | | 2016 | 1,156 | | 2015 | 1,149 | | 2014 | 1,152 | | 2013 | 1,163 | | 2012 | 1,180 | | 2011 | 1,206 | | 2010 | 1,231 | | 2009 | 1,241 | | 2008 | 1,229 | | 2007 | 1,195 | | 2006 | 1,143 | | 2005 | 1,079 | | 2004 | 1,014 | | 2003 | 959 | | 2002 | 909 | | 2001 | 864 | | 2000 | 825 | | 1999 | 796 | | 1998 | 773 | | 1997 | 754 | | 1996 | 742 | | 1995 | 728 | | 1994 | 710 | | 1993 | 687 | | 1992 | 662 | | 1991 | 635 | | 1990 | 608 | | 1989 | 581 | | 1988 | 554 | | 1987 | 527 | | 1986 | 503 | | 1985 | 481 | | 1984 | 461 | | 1983 | 442 | | 1982 | 424 | | 1981 | 409 | | 1980 | 396 | | 1979 | 383 | | 1978 | 369 | | 1977 | 356 | | 1976 | 347 | | 1975 | 339 | | 1974 | 330 | | 1973 | 322 | | 1972 | 316 | | 1971 | 306 | | 1970 | 296 | | 1969 | 287 | | 1968 | 276 | | 1967 | 264 | | 1966 | 256 | | 1965 | 246 | | 1964 | 234 | | 1963 | 223 | | 1962 | 209 | | 1961 | 195 | | 1960 | 186 |
|