Year | Value | 2022 | 49.454155143452 | 2021 | 49.408412975969 | 2020 | 49.359776444847 | 2019 | 49.310594205927 | 2018 | 49.260979649003 | 2017 | 49.216320941403 | 2016 | 49.172738043003 | 2015 | 49.129046813874 | 2014 | 49.095895173234 | 2013 | 49.073803551739 | 2012 | 49.059478201806 | 2011 | 49.044426747236 | 2010 | 49.026300764659 | 2009 | 49.011223368411 | 2008 | 48.997048503623 | 2007 | 48.983846582652 | 2006 | 48.982485096122 | 2005 | 49.013371168018 | 2004 | 49.05207978673 | 2003 | 49.058622789536 | 2002 | 49.04265550917 | 2001 | 49.144116479394 | 2000 | 49.293693977678 | 1999 | 49.340719522215 | 1998 | 49.345834149198 | 1997 | 49.421036297468 | 1996 | 49.476846305177 | 1995 | 49.422007306302 | 1994 | 49.372703147514 | 1993 | 49.324697062785 | 1992 | 49.270197937852 | 1991 | 49.213420612135 | 1990 | 49.147981357051 | 1989 | 49.08724763965 | 1988 | 49.029683755286 | 1987 | 48.96896873165 | 1986 | 48.914020926124 | 1985 | 48.871306466539 | 1984 | 48.844149776272 | 1983 | 48.833797716665 | 1982 | 48.838877907205 | 1981 | 48.859963843584 | 1980 | 48.900325764604 | 1979 | 48.957944190196 | 1978 | 49.030203586902 | 1977 | 49.111476362868 | 1976 | 49.193290979992 | 1975 | 49.270968695333 | 1974 | 49.342085018329 | 1973 | 49.404155981937 | 1972 | 49.459815763737 | 1971 | 49.507210998754 | 1970 | 49.541324382918 | 1969 | 49.562312403231 | 1968 | 49.573049465092 | 1967 | 49.579027553649 | 1966 | 49.584326921604 | 1965 | 49.592387558731 | 1964 | 49.603868086696 | 1963 | 49.618022921052 | 1962 | 49.633969959839 | 1961 | 49.650830163825 | 1960 | 49.671208087775 |
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