Year | Value | 2022 | 7.4227325045299 | 2021 | 7.5814686358565 | 2020 | 9.1784712086856 | 2019 | 8.1335668997575 | 2018 | 9.1371804961841 | 2017 | 10.223848055029 | 2016 | 9.8727384975276 | 2015 | 13.325672478824 | 2014 | 10.677909899593 | 2013 | 8.9761278393467 | 2012 | 7.6766028636413 | 2011 | 7.2300534017494 | 2010 | 8.5656772941775 | 2009 | 9.6171999922939 | 2008 | 7.3534364679783 | 2007 | 8.5270499782689 | 2006 | 7.8483652114352 | 2005 | 7.7305988748195 | 2004 | 8.0815556589824 | 2003 | 8.6871184645574 | 2002 | 9.758063800538 | 2001 | 11.419004886993 | 2000 | 10.534403313019 | 1999 | 11.381936022585 | 1998 | 14.311037450059 | 1997 | 11.000935423417 | 1996 | 8.4680777590445 | 1995 | 9.2784683901152 | 1994 | 10.644781673538 | 1993 | 12.465372282065 | 1992 | 11.284157983305 | 1991 | 12.469807991022 | 1990 | 14.024292645895 | 1989 | 13.390316581901 | 1988 | 15.151881883093 | 1987 | 16.896414193661 | 1985 | 16.995200867351 | 1984 | 19.004348363892 | 1983 | 16.972927321775 | 1982 | 17.720246395916 | 1981 | 13.265238879736 | 1980 | 12.613359238789 | 1979 | 15.768811806035 | 1978 | 16.736573791806 | 1977 | 15.64881839676 | 1973 | 10.840447591115 | 1972 | 10.081551570913 | 1971 | 8.6401941174542 | 1970 | 9.4035274306479 | 1969 | 9.5705156784069 | 1968 | 8.0874548928041 | 1967 | 11.511831393137 | 1966 | 11.324231510177 | 1965 | 7.6900893972892 | 1964 | 5.9663053975748 | 1963 | 5.9026977173161 |
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