| Year | Value | | 2014 | 1,889.5450857068 | | 2013 | 2,450.5360787847 | | 2012 | 2,400.0531527955 | | 2011 | 2,866.2930913562 | | 2010 | 3,209.3404978567 | | 2009 | 3,030.5693649766 | | 2008 | 3,070.4662696661 | | 2007 | 3,716.6380441309 | | 2006 | 3,737.4218803493 | | 2005 | 3,404.7700696781 | | 2004 | 3,118.5588625568 | | 2003 | 2,989.1887279007 | | 2002 | 2,836.6466703396 | | 2001 | 2,327.17882544 | | 2000 | 2,309.3084296353 | | 1999 | 2,270.4635312232 | | 1998 | 2,187.9307651815 | | 1997 | 1,882.1600923313 | | 1996 | 1,867.8167477375 | | 1995 | 1,851.2324894048 | | 1994 | 1,904.2095138944 | | 1993 | 1,892.2017087021 | | 1992 | 1,834.2700041846 | | 1991 | 1,734.9263732991 | | 1990 | 1,651.1749044072 | | 1989 | 1,569.233436367 | | 1988 | 1,610.3183710819 | | 1987 | 1,501.5571561827 | | 1986 | 1,102.5996615887 | | 1985 | 1,049.8565132767 | | 1984 | 1,062.9681695879 | | 1983 | 1,087.7464370755 | | 1982 | 1,124.4980411624 | | 1981 | 1,167.410825462 | | 1980 | 1,217.124804234 | | 1979 | 1,155.5186042045 | | 1978 | 986.1302775626 | | 1977 | 874.5753509809 | | 1976 | 739.51014185337 | | 1975 | 623.079873342 | | 1974 | 496.91527112853 | | 1973 | 431.80876053613 | | 1972 | 221.08549500297 | | 1971 | 203.23542628375 |
|