Year | Value | 2022 | 50.917766575596 | 2021 | 50.999693286815 | 2020 | 51.068506766572 | 2019 | 51.118905112272 | 2018 | 51.154529307282 | 2017 | 51.185705217482 | 2016 | 51.204665779565 | 2015 | 51.218046242557 | 2014 | 51.231854235259 | 2013 | 51.235923685435 | 2012 | 51.231923614259 | 2011 | 51.218457632264 | 2010 | 51.201192959344 | 2009 | 51.182629278951 | 2008 | 51.165742050111 | 2007 | 51.145058832022 | 2006 | 51.120464519371 | 2005 | 51.091991467562 | 2004 | 51.056763285024 | 2003 | 51.023800261697 | 2002 | 51.002203613927 | 2001 | 50.985999771209 | 2000 | 50.962543821883 | 1999 | 50.939953506733 | 1998 | 50.908772390838 | 1997 | 50.867198711891 | 1996 | 50.825094058973 | 1995 | 50.783891253701 | 1994 | 50.740714737064 | 1993 | 50.698374420222 | 1992 | 50.660648990479 | 1991 | 50.591416917893 | 1990 | 50.564954172482 | 1989 | 50.605413105413 | 1988 | 50.636175452372 | 1987 | 50.663863290686 | 1986 | 50.686788523001 | 1985 | 50.711413268894 | 1984 | 50.74187203727 | 1983 | 50.779512052806 | 1982 | 50.819461522932 | 1981 | 50.857280180422 | 1980 | 50.799218459248 | 1979 | 50.640893695852 | 1978 | 50.485711058398 | 1977 | 50.342657276372 | 1976 | 50.201033340018 | 1975 | 50.05727817942 | 1974 | 49.913065438898 | 1973 | 49.77041717358 | 1972 | 49.622680800849 | 1971 | 49.467898374106 | 1970 | 49.310880671142 | 1969 | 49.149558305706 | 1968 | 48.981808308444 | 1967 | 48.806975906423 | 1966 | 48.627860193423 | 1965 | 48.446363189245 | 1964 | 48.254916549143 | 1963 | 48.056138450777 | 1962 | 47.854512921097 | 1961 | 47.645506968926 | 1960 | 47.423966912682 |
|