Year | Value | 2022 | 19,821 | 2021 | 20,120 | 2020 | 20,607 | 2019 | 21,150 | 2018 | 21,731 | 2017 | 22,257 | 2016 | 22,582 | 2015 | 22,806 | 2014 | 22,935 | 2013 | 22,928 | 2012 | 22,793 | 2011 | 22,656 | 2010 | 22,576 | 2009 | 22,486 | 2008 | 22,367 | 2007 | 22,221 | 2006 | 22,002 | 2005 | 21,672 | 2004 | 21,379 | 2003 | 21,195 | 2002 | 21,058 | 2001 | 21,100 | 2000 | 21,267 | 1999 | 21,611 | 1998 | 22,081 | 1997 | 22,560 | 1996 | 22,929 | 1995 | 23,231 | 1994 | 23,420 | 1993 | 23,479 | 1992 | 23,452 | 1991 | 23,455 | 1990 | 23,534 | 1989 | 23,602 | 1988 | 23,657 | 1987 | 23,693 | 1986 | 23,681 | 1985 | 23,560 | 1984 | 23,253 | 1983 | 22,710 | 1982 | 21,912 | 1981 | 20,928 | 1980 | 19,867 | 1979 | 18,760 | 1978 | 17,693 | 1977 | 16,883 | 1976 | 16,518 | 1975 | 16,725 | 1974 | 17,421 | 1973 | 18,356 | 1972 | 19,283 | 1971 | 20,018 | 1970 | 20,458 | 1969 | 20,609 | 1968 | 20,543 | 1967 | 20,349 | 1966 | 20,099 | 1965 | 19,874 | 1964 | 19,675 | 1963 | 19,442 | 1962 | 19,101 | 1961 | 18,632 | 1960 | 18,054 |
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