Year | Value | 2021 | 11.712 | 2020 | 11.813 | 2019 | 11.994 | 2018 | 12.22 | 2017 | 12.748 | 2016 | 13.47 | 2015 | 14.123 | 2014 | 13.96 | 2013 | 14.54 | 2012 | 15.037 | 2011 | 15.264 | 2010 | 15.329 | 2009 | 16.354 | 2008 | 16.548 | 2007 | 16.673 | 2006 | 18.075 | 2005 | 18.016 | 2004 | 18.534 | 2003 | 18.519 | 2002 | 18.609 | 2001 | 18.808 | 2000 | 19.12 | 1999 | 21.139 | 1998 | 22.412 | 1997 | 22.992 | 1996 | 23.205 | 1995 | 24.994 | 1994 | 25.606 | 1993 | 25.951 | 1992 | 26.012 | 1991 | 25.695 | 1990 | 25.322 | 1989 | 26.599 | 1988 | 27.097 | 1987 | 27.62 | 1986 | 28.054 | 1985 | 28.496 | 1984 | 28.814 | 1983 | 29.065 | 1982 | 29.221 | 1981 | 29.41 | 1980 | 29.544 | 1979 | 29.535 | 1978 | 29.702 | 1977 | 29.985 | 1976 | 29.931 | 1975 | 30.962 | 1974 | 31.853 | 1973 | 32.827 | 1972 | 33.838 | 1971 | 34.625 | 1970 | 35.252 | 1969 | 35.922 | 1968 | 36.563 | 1967 | 37.138 | 1966 | 37.559 | 1965 | 37.644 | 1964 | 37.815 | 1963 | 37.394 | 1962 | 37.316 | 1961 | 38.587 | 1960 | 40.333 |
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