Year | Value | 2021 | 19.28 | 2020 | 20.006 | 2019 | 20.744 | 2018 | 21.514 | 2017 | 22.268 | 2016 | 23.016 | 2015 | 23.947 | 2014 | 25.006 | 2013 | 26.187 | 2012 | 27.379 | 2011 | 28.631 | 2010 | 30.129 | 2009 | 31.481 | 2008 | 32.48 | 2007 | 33.323 | 2006 | 33.883 | 2005 | 34.197 | 2004 | 34.375 | 2003 | 34.463 | 2002 | 34.563 | 2001 | 34.796 | 2000 | 34.976 | 1999 | 35.291 | 1998 | 35.696 | 1997 | 36.21 | 1996 | 36.973 | 1995 | 37.792 | 1994 | 38.613 | 1993 | 39.317 | 1992 | 40.12 | 1991 | 41.165 | 1990 | 42.246 | 1989 | 43.537 | 1988 | 45.004 | 1987 | 46.409 | 1986 | 47.329 | 1985 | 48.097 | 1984 | 48.734 | 1983 | 49.255 | 1982 | 49.659 | 1981 | 50.02 | 1980 | 50.311 | 1979 | 50.621 | 1978 | 50.782 | 1977 | 50.75 | 1976 | 50.582 | 1975 | 50.192 | 1974 | 49.634 | 1973 | 48.533 | 1972 | 47.658 | 1971 | 46.873 | 1970 | 46.694 | 1969 | 47.211 | 1968 | 47.885 | 1967 | 48.065 | 1966 | 47.839 | 1965 | 47.52 | 1964 | 47.182 | 1963 | 46.919 | 1962 | 46.771 | 1961 | 46.76 | 1960 | 46.838 |
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