Year | Value | 2022 | 52.130001537637 | 2021 | 52.012727148466 | 2020 | 51.791376091959 | 2019 | 51.552016837591 | 2018 | 51.292957895465 | 2017 | 51.034521592419 | 2016 | 50.773030008232 | 2015 | 50.518968239888 | 2014 | 50.289287946224 | 2013 | 50.0881092509 | 2012 | 49.914283786959 | 2011 | 49.774181896305 | 2010 | 49.671048703896 | 2009 | 49.607220216606 | 2008 | 49.582608653583 | 2007 | 49.581028972459 | 2006 | 49.599340462114 | 2005 | 49.624824479289 | 2004 | 49.644812352311 | 2003 | 49.660251794583 | 2002 | 49.670990044453 | 2001 | 49.674873368461 | 2000 | 49.680620823021 | 1999 | 49.670314129647 | 1998 | 49.644188410708 | 1997 | 49.618222451966 | 1996 | 49.595217886723 | 1995 | 49.568546729204 | 1994 | 49.527819675985 | 1993 | 49.502852833246 | 1992 | 49.489889211574 | 1991 | 49.471885425991 | 1990 | 49.462221395104 | 1989 | 49.45177317115 | 1988 | 49.433236896655 | 1987 | 49.4108438518 | 1986 | 49.380131840916 | 1985 | 49.352367967278 | 1984 | 49.307975474304 | 1983 | 49.217232549594 | 1982 | 49.096765076486 | 1981 | 48.971085833455 | 1980 | 48.864014484977 | 1979 | 48.761918594975 | 1978 | 48.647493174864 | 1977 | 48.52732805993 | 1976 | 48.395080898109 | 1975 | 48.259959514297 | 1974 | 48.13717495411 | 1973 | 48.033005158242 | 1972 | 47.96383964385 | 1971 | 47.915734419976 | 1970 | 47.88785532665 | 1969 | 47.888338700045 | 1968 | 47.906494159815 | 1967 | 47.927071912941 | 1966 | 47.952988237771 | 1965 | 48.00230391451 | 1964 | 48.049321166799 | 1963 | 48.079568871773 | 1962 | 48.104944969772 | 1961 | 48.101269577599 | 1960 | 48.073915670501 |
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