Year | Value | 2022 | 51.069262024906 | 2021 | 51.104637031596 | 2020 | 51.141273912889 | 2019 | 51.179755899247 | 2018 | 51.221571540196 | 2017 | 51.264319002114 | 2016 | 51.307491581313 | 2015 | 51.354488150306 | 2014 | 51.404540513039 | 2013 | 51.458876623113 | 2012 | 51.516853632001 | 2011 | 51.56385613522 | 2010 | 51.603307818165 | 2009 | 51.64766859188 | 2008 | 51.696402247558 | 2007 | 51.749963877567 | 2006 | 51.80887601016 | 2005 | 51.873752464881 | 2004 | 51.946216571182 | 2003 | 52.025877241715 | 2002 | 52.048420112691 | 2001 | 51.971639874362 | 2000 | 51.858344074203 | 1999 | 51.742667880379 | 1998 | 51.619497779117 | 1997 | 51.567695336161 | 1996 | 51.594071038536 | 1995 | 51.623055596048 | 1994 | 50.858315392196 | 1993 | 50.314735209507 | 1992 | 50.274159981027 | 1991 | 50.242002030276 | 1990 | 50.217487467831 | 1989 | 50.20322112626 | 1988 | 50.194600929684 | 1987 | 50.18201916943 | 1986 | 50.169765046776 | 1985 | 50.160721215711 | 1984 | 50.153044654961 | 1983 | 50.146994673171 | 1982 | 50.142599373773 | 1981 | 50.138846879969 | 1980 | 50.134024909234 | 1979 | 50.128902599611 | 1978 | 50.12611863624 | 1977 | 50.1280509578 | 1976 | 50.135482348355 | 1975 | 50.149520921857 | 1974 | 50.168100312582 | 1973 | 50.18854396448 | 1972 | 50.209148465064 | 1971 | 50.22955354668 | 1970 | 50.251323861433 | 1969 | 50.27426765124 | 1968 | 50.297787280756 | 1967 | 50.321696730856 | 1966 | 50.345686045468 | 1965 | 50.369628663176 | 1964 | 50.392414604552 | 1963 | 50.403329540744 | 1962 | 50.415198115129 | 1961 | 50.440056534152 | 1960 | 50.466562514118 |
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