Year | Value | 2021 | 35.347773707373 | 2020 | 35.192879797409 | 2019 | 35.037985887444 | 2018 | 34.883091977479 | 2017 | 34.728198067514 | 2016 | 34.573304157549 | 2015 | 34.417590703087 | 2014 | 34.262696793122 | 2013 | 34.107802883157 | 2012 | 33.952908973193 | 2011 | 33.798015063228 | 2010 | 33.643121153263 | 2009 | 33.638531704079 | 2008 | 33.454625918914 | 2007 | 33.271047951549 | 2006 | 33.16368762242 | 2005 | 33.103041329629 | 2004 | 32.528540637114 | 2003 | 33.376769191683 | 2002 | 32.522803825634 | 2001 | 32.215474639195 | 2000 | 31.687687983019 | 1999 | 30.855850318393 | 1998 | 30.855850318393 | 1997 | 30.855850318393 | 1996 | 30.036305821225 | 1995 | 29.02744654521 | 1994 | 28.905334415132 | 1993 | 27.176095526107 | 1992 | 26.432768667175 | 1991 | 26.342618772486 | 1990 | 26.330325605029 | 1989 | 26.326227882543 | 1988 | 26.326227882543 | 1987 | 26.312295626091 | 1986 | 26.312295626091 | 1985 | 26.3098369926 | 1984 | 26.293446102656 | 1983 | 26.293446102656 | 1982 | 26.293446102656 | 1981 | 26.293446102656 | 1980 | 26.290987469165 | 1979 | 26.290987469165 | 1978 | 26.286889746679 | 1977 | 26.286889746679 | 1976 | 26.288528835673 | 1975 | 26.125439480737 | 1974 | 26.084462255878 | 1973 | 26.04348503102 | 1972 | 26.04348503102 | 1971 | 26.04348503102 | 1970 | 26.04348503102 | 1969 | 26.002507806161 | 1968 | 26.002507806161 | 1967 | 26.002507806161 | 1966 | 25.997590539178 | 1965 | 25.99431236119 | 1964 | 25.990214638704 | 1963 | 25.986116916218 | 1962 | 25.982019193732 | 1961 | 25.977921471246 |
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