Year | Value | 2022 | 50.486798958326 | 2021 | 50.462071803806 | 2020 | 50.43656211099 | 2019 | 50.437008236946 | 2018 | 50.461160453234 | 2017 | 50.489278776488 | 2016 | 50.52253108566 | 2015 | 50.557748499531 | 2014 | 50.594119010379 | 2013 | 50.634125071578 | 2012 | 50.677211607148 | 2011 | 50.722839148306 | 2010 | 50.745078508425 | 2009 | 50.741408191742 | 2008 | 50.73755398806 | 2007 | 50.734826426389 | 2006 | 50.735212751663 | 2005 | 50.740406357348 | 2004 | 50.74864852319 | 2003 | 50.754291627812 | 2002 | 50.751048762739 | 2001 | 50.751430901827 | 2000 | 50.769241545054 | 1999 | 50.801892263802 | 1998 | 50.837157303936 | 1997 | 50.86515068582 | 1996 | 50.888330687882 | 1995 | 50.911302391462 | 1994 | 50.934654728044 | 1993 | 50.956707575186 | 1992 | 50.982136639779 | 1991 | 51.01373890286 | 1990 | 51.044170844705 | 1989 | 51.072694053442 | 1988 | 51.09913988493 | 1987 | 51.120012723784 | 1986 | 51.14061797676 | 1985 | 51.163692719451 | 1984 | 51.184749354589 | 1983 | 51.203520740166 | 1982 | 51.217465235238 | 1981 | 51.224674458253 | 1980 | 51.223849950572 | 1979 | 51.213145110464 | 1978 | 51.192679622358 | 1977 | 51.165275593623 | 1976 | 51.139950649042 | 1975 | 51.116073690566 | 1974 | 51.092954992759 | 1973 | 51.073437779858 | 1972 | 51.065456613648 | 1971 | 51.076626546809 | 1970 | 51.1002147774 | 1969 | 51.106917986162 | 1968 | 51.069161571387 | 1967 | 50.978953005019 | 1966 | 50.852459567596 | 1965 | 50.735264291657 | 1964 | 50.657407217651 | 1963 | 50.604241141287 | 1962 | 50.549379692672 | 1961 | 50.491130363822 | 1960 | 50.438736159162 |
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