| Year | Value | | 2022 | 10,432 | | 2021 | 10,165 | | 2020 | 9,922 | | 2019 | 9,798 | | 2018 | 9,800 | | 2017 | 9,851 | | 2016 | 9,921 | | 2015 | 10,001 | | 2014 | 10,088 | | 2013 | 10,157 | | 2012 | 10,189 | | 2011 | 10,172 | | 2010 | 10,037 | | 2009 | 9,774 | | 2008 | 9,441 | | 2007 | 9,082 | | 2006 | 8,731 | | 2005 | 8,498 | | 2004 | 8,417 | | 2003 | 8,412 | | 2002 | 8,459 | | 2001 | 8,535 | | 2000 | 8,618 | | 1999 | 8,722 | | 1998 | 8,858 | | 1997 | 9,009 | | 1996 | 9,170 | | 1995 | 9,328 | | 1994 | 9,461 | | 1993 | 9,550 | | 1992 | 9,594 | | 1991 | 9,600 | | 1990 | 9,560 | | 1989 | 9,565 | | 1988 | 9,716 | | 1987 | 9,963 | | 1986 | 10,142 | | 1985 | 10,204 | | 1984 | 10,260 | | 1983 | 10,345 | | 1982 | 10,446 | | 1981 | 10,418 | | 1980 | 10,249 | | 1979 | 10,078 | | 1978 | 9,913 | | 1977 | 9,723 | | 1976 | 9,419 | | 1975 | 9,085 | | 1974 | 8,897 | | 1973 | 8,718 | | 1972 | 8,445 | | 1971 | 8,139 | | 1970 | 7,809 | | 1969 | 7,457 | | 1968 | 7,133 | | 1967 | 6,831 | | 1966 | 6,528 | | 1965 | 6,238 | | 1964 | 5,980 | | 1963 | 5,749 | | 1962 | 5,550 | | 1961 | 5,390 | | 1960 | 5,229 |
|