| Year | Value | | 2014 | 1,243.8467589066 | | 2013 | 1,334.1769583279 | | 2012 | 1,074.6078328106 | | 2011 | 1,247.1407722655 | | 2010 | 1,176.783850887 | | 2009 | 825.61216862601 | | 2008 | 747.44045537636 | | 2007 | 761.59541049794 | | 2006 | 932.3450637103 | | 2005 | 784.73981594417 | | 2004 | 1,135.5776966165 | | 2003 | 985.37716250167 | | 2002 | 1,201.1650352464 | | 2001 | 1,181.2867967297 | | 2000 | 1,183.9769428205 | | 1999 | 1,224.1436388988 | | 1998 | 1,264.8845155232 | | 1997 | 1,305.8215189176 | | 1996 | 1,321.9909006433 | | 1995 | 1,365.5636980307 | | 1994 | 1,325.9533388684 | | 1993 | 1,302.4583876154 | | 1992 | 1,311.6734970757 | | 1991 | 1,098.8224053082 | | 1990 | 1,291.1715972149 | | 1989 | 1,299.1189955162 | | 1988 | 1,309.798481764 | | 1987 | 1,285.2136149501 | | 1986 | 1,311.1661030648 | | 1985 | 1,264.7062408086 | | 1984 | 1,202.1825798372 | | 1983 | 1,031.6875559465 | | 1982 | 897.2411751931 | | 1981 | 733.19182271459 | | 1980 | 792.03894657795 | | 1979 | 727.90718937753 | | 1978 | 580.59049243481 | | 1977 | 487.57317428201 | | 1976 | 414.7727433721 | | 1975 | 367.37294430822 | | 1974 | 325.70954784364 | | 1973 | 307.48319167001 | | 1972 | 262.19828757394 | | 1971 | 261.9417882628 |
|