Year | Value | 2021 | 13.699 | 2020 | 14.231 | 2019 | 15.118 | 2018 | 17.231 | 2017 | 18.608 | 2016 | 19.017 | 2015 | 19.428 | 2014 | 19.824 | 2013 | 19.445 | 2012 | 18.926 | 2011 | 18.164 | 2010 | 17.755 | 2009 | 17.548 | 2008 | 17.264 | 2007 | 16.897 | 2006 | 16.489 | 2005 | 16.199 | 2004 | 16.068 | 2003 | 15.958 | 2002 | 16.069 | 2001 | 16.276 | 2000 | 16.39 | 1999 | 16.56 | 1998 | 16.802 | 1997 | 17.338 | 1996 | 18.593 | 1995 | 20.448 | 1994 | 22.778 | 1993 | 26.089 | 1992 | 28.549 | 1991 | 30.928 | 1990 | 32.46 | 1989 | 34.106 | 1988 | 35.961 | 1987 | 37.926 | 1986 | 40.046 | 1985 | 41.792 | 1984 | 43.119 | 1983 | 43.871 | 1982 | 44.393 | 1981 | 44.063 | 1980 | 44.357 | 1979 | 44.21 | 1978 | 43.061 | 1977 | 42.262 | 1976 | 41.815 | 1975 | 40.796 | 1974 | 40.632 | 1973 | 40.635 | 1972 | 41.134 | 1971 | 42.365 | 1970 | 43.24 | 1969 | 44.164 | 1968 | 44.506 | 1967 | 44.939 | 1966 | 45.123 | 1965 | 45.481 | 1964 | 45.916 | 1963 | 46.611 | 1962 | 47.354 | 1961 | 47.959 | 1960 | 49.046 |
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