| Year | Value | | 2022 | 36,616 | | 2021 | 36,470 | | 2020 | 36,701 | | 2019 | 36,640 | | 2018 | 36,303 | | 2017 | 36,090 | | 2016 | 36,138 | | 2015 | 36,536 | | 2014 | 37,306 | | 2013 | 38,433 | | 2012 | 39,554 | | 2011 | 40,088 | | 2010 | 39,762 | | 2009 | 38,927 | | 2008 | 37,671 | | 2007 | 36,136 | | 2006 | 34,849 | | 2005 | 33,987 | | 2004 | 33,266 | | 2003 | 32,621 | | 2002 | 32,292 | | 2001 | 32,276 | | 2000 | 32,357 | | 1999 | 32,503 | | 1998 | 33,386 | | 1997 | 35,334 | | 1996 | 37,892 | | 1995 | 41,294 | | 1994 | 45,861 | | 1993 | 50,807 | | 1992 | 55,655 | | 1991 | 59,476 | | 1990 | 61,374 | | 1989 | 61,866 | | 1988 | 61,842 | | 1987 | 61,225 | | 1986 | 60,303 | | 1985 | 59,620 | | 1984 | 58,739 | | 1983 | 57,561 | | 1982 | 56,701 | | 1981 | 56,139 | | 1980 | 55,665 | | 1979 | 55,495 | | 1978 | 55,392 | | 1977 | 55,254 | | 1976 | 55,260 | | 1975 | 55,250 | | 1974 | 54,847 | | 1973 | 54,195 | | 1972 | 53,006 | | 1971 | 51,224 | | 1970 | 49,676 | | 1969 | 49,035 | | 1968 | 48,797 | | 1967 | 49,085 | | 1966 | 49,922 | | 1965 | 50,475 | | 1964 | 50,612 | | 1963 | 50,421 | | 1962 | 49,902 | | 1961 | 49,173 | | 1960 | 48,841 |
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