Year | Value | 2021 | 22.4 | 2020 | 24 | 2019 | 26.9 | 2018 | 27.1 | 2017 | 24.8 | 2016 | 26 | 2015 | 27.4 | 2014 | 27.7 | 2013 | 27.2 | 2012 | 27.6 | 2011 | 27.1 | 2010 | 26.8 | 2009 | 25.2 | 2008 | 23.9 | 2007 | 23.4 | 2006 | 23.1 | 2005 | 21.3 | 2004 | 21.5 | 2003 | 20.9 | 2002 | 20.2 | 2001 | 19.8 | 2000 | 19.8 | 1999 | 21.5 | 1998 | 21.7 | 1997 | 21.6 | 1996 | 23.2 | 1995 | 25.6 | 1994 | 24.3 | 1993 | 25.7 | 1992 | 28.2 | 1991 | 28.8 | 1990 | 29.1 | 1989 | 30.4 | 1988 | 31.5 | 1987 | 32.7 | 1986 | 32.7 | 1985 | 32 | 1984 | 32 | 1983 | 31.3 | 1982 | 31.1 | 1981 | 30.7 | 1980 | 29.6 | 1979 | 31.4 | 1978 | 31.765 | 1977 | 31.959 | 1976 | 31.966 | 1975 | 32.028 | 1974 | 32.273 | 1973 | 32.886 | 1972 | 33.489 | 1971 | 33.389 | 1970 | 33.411 | 1969 | 33.428 | 1968 | 33.656 | 1967 | 34.527 | 1966 | 35.597 | 1965 | 36.999 | 1964 | 38.315 | 1963 | 39.748 | 1962 | 40.729 | 1961 | 41.414 | 1960 | 41.786 |
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