| Year | Value | | 2021 | 338,980 | | 2020 | 338,950 | | 2019 | 338,300 | | 2018 | 335,940 | | 2017 | 333,210 | | 2016 | 326,720 | | 2015 | 324,500 | | 2014 | 322,490 | | 2013 | 314,300 | | 2012 | 308,860 | | 2011 | 296,360 | | 2010 | 284,290 | | 2009 | 268,870 | | 2008 | 257,000 | | 2007 | 256,500 | | 2006 | 255,860 | | 2005 | 255,500 | | 2004 | 255,500 | | 2003 | 255,500 | | 2002 | 255,500 | | 2001 | 255,500 | | 2000 | 256,000 | | 1999 | 256,000 | | 1998 | 257,000 | | 1997 | 257,000 | | 1996 | 258,000 | | 1995 | 258,000 | | 1994 | 260,000 | | 1993 | 260,000 | | 1992 | 260,000 | | 1991 | 259,800 | | 1990 | 259,600 | | 1989 | 259,500 | | 1988 | 259,500 | | 1987 | 259,500 | | 1986 | 259,500 | | 1985 | 259,000 | | 1984 | 258,500 | | 1983 | 258,000 | | 1982 | 257,700 | | 1981 | 257,500 | | 1980 | 257,000 | | 1979 | 256,500 | | 1978 | 256,500 | | 1977 | 256,300 | | 1976 | 256,000 | | 1975 | 255,500 | | 1974 | 255,500 | | 1973 | 255,000 | | 1972 | 254,500 | | 1971 | 254,000 | | 1970 | 253,500 | | 1969 | 253,000 | | 1968 | 252,500 | | 1967 | 252,000 | | 1966 | 251,700 | | 1965 | 251,500 | | 1964 | 251,300 | | 1963 | 251,000 | | 1962 | 250,700 | | 1961 | 250,500 |
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