| Year | Value | | 2021 | 19,023,454.529 | | 2020 | 19,017,642.13 | | 2019 | 18,980,143.84 | | 2018 | 18,996,888.041 | | 2017 | 19,010,295.195 | | 2016 | 19,016,818.442 | | 2015 | 19,028,681.718 | | 2014 | 19,025,154.915 | | 2013 | 19,065,484.805 | | 2012 | 19,066,840.267 | | 2011 | 19,062,587.484 | | 2010 | 19,084,719 | | 2009 | 19,005,921.61 | | 2008 | 19,026,770.34 | | 2007 | 19,085,409.63 | | 2006 | 19,072,345.622 | | 2005 | 19,074,521.631 | | 2004 | 19,066,332.016 | | 2003 | 19,052,058.372 | | 2002 | 19,040,739.6 | | 2001 | 19,029,806.523 | | 2000 | 19,045,736.231 | | 1999 | 19,027,243.078 | | 1998 | 19,005,265.235 | | 1997 | 19,000,599.772 | | 1996 | 18,972,373.425 | | 1995 | 18,980,740.927 | | 1994 | 19,047,416.876 | | 1993 | 19,023,699.333 | | 1992 | 19,007,223.085 | | 1991 | 18,988,698.018 | | 1990 | 18,957,457.891 | | 1989 | 18,862,918.564 | | 1988 | 18,790,989.936 | | 1987 | 18,726,346.309 | | 1986 | 18,628,693.482 | | 1985 | 18,545,436.825 | | 1984 | 18,363,237.227 | | 1983 | 18,215,208.2 | | 1982 | 18,062,740.473 | | 1981 | 17,948,389.245 | | 1980 | 17,863,671.198 | | 1979 | 17,756,760.991 | | 1978 | 17,643,762.664 | | 1977 | 17,514,895.503 | | 1976 | 17,387,249.742 | | 1975 | 17,267,130.382 | | 1974 | 17,178,851.455 | | 1973 | 17,068,175.427 | | 1972 | 16,959,495.6 | | 1971 | 16,846,345.1 | | 1970 | 16,745,658.4 | | 1969 | 16,657,758.7 | | 1968 | 16,576,633.3 | | 1967 | 16,498,318.1 | | 1966 | 16,434,023.6 | | 1965 | 16,364,107.7 | | 1964 | 16,299,045.5 | | 1963 | 16,241,025 | | 1962 | 16,175,216.8 | | 1961 | 16,114,384.7 |
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