| Year | Value | | 2019 | 2,389 | | 2018 | 2,328 | | 2017 | 2,248 | | 2016 | 2,166 | | 2015 | 2,099 | | 2014 | 1,984 | | 2013 | 1,931 | | 2012 | 1,941 | | 2011 | 1,981 | | 2010 | 2,001 | | 2009 | 1,945 | | 2008 | 1,839 | | 2007 | 1,707 | | 2006 | 1,590 | | 2005 | 1,505 | | 2004 | 1,484 | | 2003 | 1,462 | | 2002 | 1,418 | | 2001 | 1,356 | | 2000 | 1,296 | | 1999 | 1,276 | | 1998 | 1,287 | | 1997 | 1,315 | | 1996 | 1,347 | | 1995 | 1,377 | | 1994 | 1,367 | | 1993 | 1,362 | | 1992 | 1,366 | | 1991 | 1,367 | | 1990 | 1,358 | | 1989 | 1,372 | | 1988 | 1,368 | | 1987 | 1,354 | | 1986 | 1,344 | | 1985 | 1,350 | | 1984 | 1,418 | | 1983 | 1,491 | | 1982 | 1,561 | | 1981 | 1,622 | | 1980 | 1,672 | | 1979 | 1,651 | | 1978 | 1,625 | | 1977 | 1,593 | | 1976 | 1,559 | | 1975 | 1,518 | | 1974 | 1,459 | | 1973 | 1,398 | | 1972 | 1,334 | | 1971 | 1,271 | | 1970 | 1,206 | | 1969 | 1,151 | | 1968 | 1,097 | | 1967 | 1,050 | | 1966 | 1,011 | | 1965 | 982 | | 1964 | 946 | | 1963 | 918 | | 1962 | 900 | | 1961 | 890 | | 1960 | 887 |
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