| Year | Value | | 2022 | 1,601 | | 2021 | 1,554 | | 2020 | 1,506 | | 2019 | 1,453 | | 2018 | 1,402 | | 2017 | 1,364 | | 2016 | 1,344 | | 2015 | 1,346 | | 2014 | 1,374 | | 2013 | 1,420 | | 2012 | 1,470 | | 2011 | 1,512 | | 2010 | 1,541 | | 2009 | 1,556 | | 2008 | 1,559 | | 2007 | 1,551 | | 2006 | 1,539 | | 2005 | 1,529 | | 2004 | 1,516 | | 2003 | 1,498 | | 2002 | 1,478 | | 2001 | 1,447 | | 2000 | 1,387 | | 1999 | 1,314 | | 1998 | 1,251 | | 1997 | 1,195 | | 1996 | 1,154 | | 1995 | 1,125 | | 1994 | 1,103 | | 1993 | 1,078 | | 1992 | 1,054 | | 1991 | 1,028 | | 1990 | 1,017 | | 1989 | 1,021 | | 1988 | 1,032 | | 1987 | 1,045 | | 1986 | 1,057 | | 1985 | 1,064 | | 1984 | 1,069 | | 1983 | 1,077 | | 1982 | 1,089 | | 1981 | 1,099 | | 1980 | 1,108 | | 1979 | 1,120 | | 1978 | 1,122 | | 1977 | 1,110 | | 1976 | 1,092 | | 1975 | 1,068 | | 1974 | 1,044 | | 1973 | 1,021 | | 1972 | 1,001 | | 1971 | 975 | | 1970 | 944 | | 1969 | 917 | | 1968 | 897 | | 1967 | 884 | | 1966 | 879 | | 1965 | 881 | | 1964 | 886 | | 1963 | 889 | | 1962 | 889 | | 1961 | 882 | | 1960 | 868 |
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