Year | Value | 2021 | 10.020653166431 | 2020 | 9.842708850732 | 2019 | 8.8959375351754 | 2018 | 8.9207549738422 | 2017 | 8.8654173357636 | 2016 | 8.6882592972697 | 2015 | 8.7349918152386 | 2014 | 8.4360198928432 | 2013 | 8.4956272773554 | 2012 | 8.4793829188664 | 2011 | 8.3533524282514 | 2010 | 8.3141796584288 | 2009 | 8.2649643301135 | 2008 | 8.3533359990705 | 2007 | 8.288306938307 | 2006 | 8.257670341233 | 2005 | 8.4143651049644 | 2004 | 8.2848435905138 | 2003 | 8.5297769582991 | 2002 | 8.4688381856544 | 2001 | 8.4294665929727 | 2000 | 8.4904774126543 | 1999 | 8.6535898785747 | 1998 | 8.6247953083731 | 1997 | 8.6402112537994 | 1996 | 8.7205561281531 | 1995 | 8.772564661936 | 1994 | 8.7112479891691 | 1993 | 8.8037169320492 | 1992 | 8.6633222363672 | 1991 | 8.7448825438878 | 1990 | 8.7613563075986 | 1989 | 8.7654312958766 | 1988 | 8.7967121857431 | 1987 | 8.7152606972241 | 1986 | 8.8150600737862 | 1985 | 8.8963798057435 | 1984 | 8.7995128889679 | 1983 | 8.8977053821502 | 1982 | 8.7638387684209 | 1981 | 8.8557368612213 | 1980 | 9.0379185852084 | 1979 | 8.853777227258 | 1978 | 8.9827102217037 | 1977 | 8.9212049868695 | 1976 | 9.1523037648059 | 1975 | 9.168837494054 | 1974 | 9.2017803758787 | 1973 | 9.3617864304692 | 1972 | 9.2877216703408 | 1971 | 9.3789313799718 | 1970 | 9.507894299076 | 1969 | 9.614955527527 | 1968 | 9.623497601164 | 1967 | 9.370224090947 | 1966 | 9.4299048592133 | 1965 | 9.5241390615487 | 1964 | 9.4264566495614 | 1963 | 9.7116884030748 | 1962 | 9.7857652899969 | 1961 | 9.5833002952677 | 1960 | 9.7448412312071 |
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