Year | Value | 2021 | 33.92086978348 | 2020 | 33.587493169774 | 2019 | 33.823134907356 | 2018 | 33.719325576917 | 2017 | 34.119189081405 | 2016 | 33.372807948509 | 2015 | 33.563716988157 | 2014 | 34.323572074463 | 2013 | 34.303971506374 | 2012 | 34.717275066442 | 2011 | 35.052802351459 | 2010 | 34.662612314543 | 2009 | 35.057510534765 | 2008 | 35.343826612205 | 2007 | 35.748660868304 | 2006 | 36.14241917898 | 2005 | 36.2619757285 | 2004 | 35.844759368809 | 2003 | 37.076613672993 | 2002 | 37.358451621486 | 2001 | 37.690108059661 | 2000 | 37.79948071601 | 1999 | 37.792175500654 | 1998 | 38.110505559058 | 1997 | 38.051391976445 | 1996 | 38.202848299681 | 1995 | 38.257928705301 | 1994 | 38.536870858375 | 1993 | 38.353480214419 | 1992 | 38.57472241188 | 1991 | 38.554909837676 | 1990 | 38.637570722362 | 1989 | 38.728098978226 | 1988 | 38.834942891726 | 1987 | 38.817460836692 | 1986 | 38.832580193076 | 1985 | 39.353405438025 | 1984 | 39.345609172551 | 1983 | 39.25122376985 | 1982 | 39.424592341329 | 1981 | 39.535098926908 | 1980 | 39.542749866266 | 1979 | 39.497019125778 | 1978 | 39.585936046984 | 1977 | 39.509296656146 | 1976 | 39.779100542714 | 1975 | 39.738081615166 | 1974 | 39.759940959964 | 1973 | 39.731015134566 | 1972 | 39.818686188211 | 1971 | 39.82326715606 | 1970 | 39.699931532416 | 1969 | 40.297157486265 | 1968 | 40.36672993819 | 1967 | 39.689977346323 | 1966 | 39.637402647972 | 1965 | 39.62530984512 | 1964 | 39.56913653629 | 1963 | 39.555519440958 | 1962 | 39.516301719967 | 1961 | 39.517624739941 |
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