Year | Value | 2022 | 27.489998597466 | 2021 | 27.325029247815 | 2020 | 27.351039800607 | 2019 | 26.76295358244 | 2018 | 25.739283747034 | 2017 | 25.083940105209 | 2016 | 24.647209465599 | 2015 | 24.741061877193 | 2014 | 25.407175096468 | 2013 | 25.949434561811 | 2012 | 25.737172423203 | 2011 | 25.124614019403 | 2010 | 24.25071666013 | 2009 | 23.394217381638 | 2008 | 23.567501248029 | 2007 | 25.207789962278 | 2006 | 28.319902271787 | 2005 | 31.734279082372 | 2004 | 32.80921609938 | 2003 | 32.562305868208 | 2002 | 32.622906226426 | 2001 | 32.708435531082 | 2000 | 32.83942551673 | 1999 | 32.991576743594 | 1998 | 33.170567145786 | 1997 | 33.354159439584 | 1996 | 33.37968692432 | 1995 | 33.2518009912 | 1994 | 33.118360319803 | 1993 | 32.976230400316 | 1992 | 32.825015436257 | 1991 | 32.665623918368 | 1990 | 32.494028414558 | 1989 | 32.30810314456 | 1988 | 32.105682022216 | 1987 | 31.882201660329 | 1986 | 31.679604946538 | 1985 | 31.676724939049 | 1984 | 31.852079450725 | 1983 | 32.038952471448 | 1982 | 32.247735182721 | 1981 | 32.491089807282 | 1980 | 32.781041629122 | 1979 | 33.129647268481 | 1978 | 33.547597937806 | 1977 | 34.042178565612 | 1976 | 34.624863737618 | 1975 | 35.312213204268 | 1974 | 36.131824494281 | 1973 | 37.1205736133 | 1972 | 38.321940433335 | 1971 | 39.801346396586 | 1970 | 41.660240494208 | 1969 | 42.940382904216 | 1968 | 43.31663477457 | 1967 | 43.770374589479 | 1966 | 44.29427375448 | 1965 | 44.871458754222 | 1964 | 45.535450452799 | 1963 | 46.317958783121 | 1962 | 47.213172883009 | 1961 | 48.201241554686 | 1960 | 49.042187714718 |
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