| Year | Value | | 2012 | 143.19997947358 | | 2011 | 104.75316388886 | | 2010 | 100 | | 2009 | 95.787813442775 | | 2008 | 93.069353382048 | | 2007 | 80.40873633865 | | 2006 | 77.384764539745 | | 2005 | 70.334369586373 | | 2004 | 65.585733340258 | | 2003 | 62.801647524565 | | 2002 | 59.360613972656 | | 2001 | 59.438183942474 | | 2000 | 57.706974701431 | | 1999 | 60.015253689488 | | 1998 | 62.323532677545 | | 1997 | 62.824346779418 | | 1996 | 61.661345142846 | | 1995 | 56.962039486937 | | 1994 | 52.752418730636 | | 1993 | 45.741021304413 | | 1992 | 40.399004217766 | | 1991 | 36.392491402781 | | 1990 | 33.387606791542 | | 1989 | 27.963553456722 | | 1988 | 25.102109471032 | | 1987 | 18.654649846623 | | 1986 | 11.696851619139 | | 1985 | 8.5966128325452 | | 1984 | 7.3316826586135 | | 1983 | 6.7121807179825 | | 1982 | 6.3246508696582 | | 1981 | 5.5332166723763 | | 1980 | 4.6735553891218 | | 1979 | 3.9175992765456 | | 1978 | 3.7470315616141 | | 1977 | 3.5750993049632 | | 1976 | 3.1930276235168 | | 1975 | 2.8655376108484 | | 1974 | 2.5707965994468 | | 1973 | 2.2252530380431 | | 1972 | 1.8488361687477 | | 1971 | 1.8108382513424 | | 1970 | 1.7146560229105 | | 1969 | 1.6386601881001 | | 1968 | 1.6719083658296 | | 1967 | 1.625598403992 | | 1966 | 1.5270413057222 | | 1965 | 1.4712318645333 | | 1964 | 1.530603610479 | | 1963 | 1.4522329058307 | | 1962 | 1.4249219026957 | | 1961 | 1.4819187788035 | | 1960 | 1.4534473315582 |
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