Year | Value | 2022 | 50.267159524894 | 2021 | 50.293907063493 | 2020 | 50.321124649885 | 2019 | 50.343422009535 | 2018 | 50.361041747424 | 2017 | 50.375803676537 | 2016 | 50.387082101433 | 2015 | 50.397398183845 | 2014 | 50.408167009099 | 2013 | 50.414790671123 | 2012 | 50.417621405869 | 2011 | 50.421274110875 | 2010 | 50.420121203108 | 2009 | 50.425520080098 | 2008 | 50.437886370327 | 2007 | 50.44461892415 | 2006 | 50.458291402617 | 2005 | 50.473228772309 | 2004 | 50.472908702597 | 2003 | 50.463753857162 | 2002 | 50.445567540539 | 2001 | 50.42162432558 | 2000 | 50.406860682667 | 1999 | 50.456790898251 | 1998 | 50.566396782938 | 1997 | 50.682515544438 | 1996 | 50.780340298777 | 1995 | 50.868319918788 | 1994 | 50.904964903899 | 1993 | 50.851645760634 | 1992 | 50.75466747009 | 1991 | 50.700508827307 | 1990 | 50.696226281148 | 1989 | 50.693210463242 | 1988 | 50.689041658332 | 1987 | 50.690936507082 | 1986 | 50.695266435833 | 1985 | 50.70027055908 | 1984 | 50.707831149247 | 1983 | 50.713744543192 | 1982 | 50.721391803603 | 1981 | 50.732831620634 | 1980 | 50.742473689039 | 1979 | 50.752894190032 | 1978 | 50.768931553283 | 1977 | 50.809762773723 | 1976 | 50.877525436576 | 1975 | 50.948287421224 | 1974 | 50.990053697828 | 1973 | 50.999389566279 | 1972 | 51.006183249016 | 1971 | 51.01280635538 | 1970 | 51.024767329502 | 1969 | 51.039555524495 | 1968 | 51.050348316023 | 1967 | 51.05858361142 | 1966 | 51.077446223207 | 1965 | 51.09438720227 | 1964 | 51.108041681055 | 1963 | 51.130700615604 | 1962 | 51.136363636364 | 1961 | 51.129861095528 | 1960 | 51.125947983064 |
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