Year | Value | 2021 | 2.081 | 2020 | 1.971 | 2019 | 2.011 | 2018 | 2.114 | 2017 | 2.144 | 2016 | 2.198 | 2015 | 2.204 | 2014 | 2.115 | 2013 | 2.017 | 2012 | 1.938 | 2011 | 1.918 | 2010 | 1.919 | 2009 | 1.871 | 2008 | 1.762 | 2007 | 1.674 | 2006 | 1.622 | 2005 | 1.61 | 2004 | 1.592 | 2003 | 1.55 | 2002 | 1.563 | 2001 | 1.57 | 2000 | 1.601 | 1999 | 1.629 | 1998 | 1.687 | 1997 | 1.742 | 1996 | 1.792 | 1995 | 1.853 | 1994 | 1.917 | 1993 | 2.012 | 1992 | 2.134 | 1991 | 2.262 | 1990 | 2.306 | 1989 | 2.259 | 1988 | 2.232 | 1987 | 2.253 | 1986 | 2.321 | 1985 | 2.344 | 1984 | 2.337 | 1983 | 2.309 | 1982 | 2.295 | 1981 | 2.311 | 1980 | 2.327 | 1979 | 2.364 | 1978 | 2.399 | 1977 | 2.427 | 1976 | 2.487 | 1975 | 2.53 | 1974 | 2.55 | 1973 | 2.606 | 1972 | 2.658 | 1971 | 2.677 | 1970 | 2.67 | 1969 | 2.667 | 1968 | 2.679 | 1967 | 2.732 | 1966 | 2.729 | 1965 | 2.781 | 1964 | 2.87 | 1963 | 2.949 | 1962 | 2.937 | 1961 | 2.943 | 1960 | 2.942 |
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