Year | Value | 2021 | 37.717996270384 | 2020 | 37.707171775586 | 2019 | 37.644562616432 | 2018 | 37.656533369011 | 2017 | 37.637627377413 | 2016 | 37.607591796042 | 2015 | 37.581567835484 | 2014 | 37.52961049182 | 2013 | 37.54839121676 | 2012 | 37.491357973642 | 2011 | 37.469661102588 | 2010 | 37.437510395042 | 2009 | 37.305424532481 | 2008 | 37.266663372026 | 2007 | 37.314804367991 | 2006 | 37.254966700074 | 2005 | 37.202016005044 | 2004 | 37.282173904048 | 2003 | 37.297660363571 | 2002 | 37.390235492613 | 2001 | 37.348360251612 | 2000 | 37.310556932336 | 1999 | 37.281502490344 | 1998 | 37.203003352292 | 1997 | 37.145752488876 | 1996 | 36.946840089483 | 1995 | 36.907656545198 | 1994 | 36.900791739223 | 1993 | 36.801028579722 | 1992 | 36.949021322856 | 1991 | 39.705274001424 | 1990 | 39.586207595445 | 1989 | 39.438038711448 | 1988 | 39.272919532295 | 1987 | 39.114331369229 | 1986 | 38.906591891995 | 1985 | 38.740620800993 | 1984 | 38.416770445977 | 1983 | 38.154269830316 | 1982 | 37.940364167661 | 1981 | 37.723339289882 | 1980 | 37.642893047297 | 1979 | 37.48417601779 | 1978 | 37.315105520461 | 1977 | 37.097060995669 | 1976 | 36.891685136081 | 1975 | 36.9129062753 | 1974 | 36.762432457301 | 1973 | 36.598423312606 | 1972 | 36.41140764624 | 1971 | 36.19982022909 | 1970 | 36.019827869284 | 1969 | 35.871400222828 | 1968 | 35.761611476902 | 1967 | 35.622119301511 | 1966 | 35.509742825347 | 1965 | 35.393105105921 | 1964 | 35.26209393765 | 1963 | 35.141093085955 | 1962 | 35.020109354954 | 1961 | 34.896642566576 |
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