Year | Value | 2022 | 20,028 | 2021 | 20,173 | 2020 | 20,091 | 2019 | 20,031 | 2018 | 20,145 | 2017 | 20,375 | 2016 | 20,738 | 2015 | 21,259 | 2014 | 21,818 | 2013 | 22,374 | 2012 | 22,835 | 2011 | 23,075 | 2010 | 23,318 | 2009 | 23,559 | 2008 | 23,605 | 2007 | 23,501 | 2006 | 23,398 | 2005 | 23,351 | 2004 | 23,259 | 2003 | 23,087 | 2002 | 22,871 | 2001 | 22,635 | 2000 | 22,339 | 1999 | 22,243 | 1998 | 22,251 | 1997 | 22,316 | 1996 | 22,499 | 1995 | 22,767 | 1994 | 23,050 | 1993 | 23,346 | 1992 | 23,620 | 1991 | 23,972 | 1990 | 24,453 | 1989 | 24,942 | 1988 | 25,367 | 1987 | 25,661 | 1986 | 25,766 | 1985 | 25,687 | 1984 | 25,445 | 1983 | 25,070 | 1982 | 24,615 | 1981 | 24,187 | 1980 | 23,940 | 1979 | 23,812 | 1978 | 23,572 | 1977 | 23,105 | 1976 | 22,318 | 1975 | 21,187 | 1974 | 19,818 | 1973 | 18,452 | 1972 | 17,374 | 1971 | 16,864 | 1970 | 17,143 | 1969 | 18,186 | 1968 | 19,708 | 1967 | 21,350 | 1966 | 22,684 | 1965 | 23,354 | 1964 | 23,274 | 1963 | 22,642 | 1962 | 21,731 | 1961 | 20,860 | 1960 | 20,318 |
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