Year | Value | 2021 | 7.441 | 2020 | 7.974 | 2019 | 7.851 | 2018 | 9.855 | 2017 | 11.767 | 2016 | 12.45 | 2015 | 13.052 | 2014 | 13.105 | 2013 | 13.154 | 2012 | 12.597 | 2011 | 11.849 | 2010 | 8.757 | 2009 | 9.087 | 2008 | 8.517 | 2007 | 8.8 | 2006 | 10.49 | 2005 | 11.049 | 2004 | 10.32 | 2003 | 10.91 | 2002 | 10.01 | 2001 | 9.26 | 2000 | 8.98 | 1999 | 7.95 | 1998 | 8.03 | 1997 | 8.37 | 1996 | 9 | 1995 | 11.04 | 1994 | 10.93 | 1993 | 10.92 | 1992 | 8.92 | 1991 | 9.38 | 1990 | 8.43 | 1989 | 7.06 | 1984 | 5.89 | 1983 | 6.47 | 1982 | 5.21 | 1981 | 4.97 | 1980 | 5.18 | 1979 | 4.55 | 1978 | 3.64 | 1977 | 3.13 | 1975 | 2.57 | 1974 | 2.3 | 1973 | 1.71 | 1972 | 1.53 | 1971 | 1.82 | 1970 | 2.4 |
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