Year | Value | 2022 | 49.427557463212 | 2021 | 49.419205562847 | 2020 | 49.411442085651 | 2019 | 49.401120518689 | 2018 | 49.388388577651 | 2017 | 49.374281413906 | 2016 | 49.35790214053 | 2015 | 49.342508054598 | 2014 | 49.328364654273 | 2013 | 49.313741590719 | 2012 | 49.298896487305 | 2011 | 49.283182718443 | 2010 | 49.266242327734 | 2009 | 49.248554070936 | 2008 | 49.229012145851 | 2007 | 49.20930416739 | 2006 | 49.190515584997 | 2005 | 49.170804380391 | 2004 | 49.150517084085 | 2003 | 49.131185010744 | 2002 | 49.120117167374 | 2001 | 49.124701245521 | 2000 | 49.132124790061 | 1999 | 49.142847853533 | 1998 | 49.156028191569 | 1997 | 49.153636175719 | 1996 | 49.141194506148 | 1995 | 49.12843376267 | 1994 | 49.148668577572 | 1993 | 49.212832684091 | 1992 | 49.271320411697 | 1991 | 49.307248012073 | 1990 | 49.349984334629 | 1989 | 49.407701281997 | 1988 | 49.470152648296 | 1987 | 49.541740800521 | 1986 | 49.60828734447 | 1985 | 49.6659235167 | 1984 | 49.729987475179 | 1983 | 49.800139208881 | 1982 | 49.869232131074 | 1981 | 49.936980512097 | 1980 | 50.010534154249 | 1979 | 50.090287245727 | 1978 | 50.175832744651 | 1977 | 50.267888462232 | 1976 | 50.366159426871 | 1975 | 50.468389652756 | 1974 | 50.5705260453 | 1973 | 50.674436740582 | 1972 | 50.784408641936 | 1971 | 50.899741931787 | 1970 | 51.020000995074 | 1969 | 51.047030338443 | 1968 | 50.938984217145 | 1967 | 50.786365961545 | 1966 | 50.635609475235 | 1965 | 50.511646133534 | 1964 | 50.423191571457 | 1963 | 50.365020205088 | 1962 | 50.326203499113 | 1961 | 50.299053559119 | 1960 | 50.156210479551 |
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