Year | Value | 2022 | 51.674729184385 | 2021 | 51.658867264771 | 2020 | 51.649889307628 | 2019 | 51.643837673368 | 2018 | 51.640091709412 | 2017 | 51.637497804552 | 2016 | 51.63446574576 | 2015 | 51.630229220858 | 2014 | 51.624980375773 | 2013 | 51.618926479723 | 2012 | 51.613596244613 | 2011 | 51.606079961299 | 2010 | 51.596277383107 | 2009 | 51.586978085364 | 2008 | 51.577397252206 | 2007 | 51.565942885184 | 2006 | 51.553646103073 | 2005 | 51.541813389469 | 2004 | 51.529336030991 | 2003 | 51.519940426192 | 2002 | 51.512655983501 | 2001 | 51.503077907342 | 2000 | 51.493762436301 | 1999 | 51.485551326524 | 1998 | 51.476063915875 | 1997 | 51.464747286377 | 1996 | 51.451537435162 | 1995 | 51.435670354801 | 1994 | 51.416855808219 | 1993 | 51.397226740575 | 1992 | 51.378523034449 | 1991 | 51.359903921276 | 1990 | 51.341821711443 | 1989 | 51.323360669659 | 1988 | 51.304152610668 | 1987 | 51.283673110348 | 1986 | 51.263611683952 | 1985 | 51.24514894415 | 1984 | 51.226202904935 | 1983 | 51.20911107391 | 1982 | 51.194711394106 | 1981 | 51.182761850403 | 1980 | 51.1718322823 | 1979 | 51.159134624464 | 1978 | 51.146215248133 | 1977 | 51.135331094637 | 1976 | 51.127440449859 | 1975 | 51.12337781313 | 1974 | 51.125584776129 | 1973 | 51.135925904303 | 1972 | 51.150947912972 | 1971 | 51.169283575438 | 1970 | 51.191993774947 | 1969 | 51.213300667803 | 1968 | 51.234213661538 | 1967 | 51.258825234982 | 1966 | 51.28600105589 | 1965 | 51.315309800924 | 1964 | 51.346630381559 | 1963 | 51.380804926491 | 1962 | 51.417447884686 | 1961 | 51.45487628359 | 1960 | 51.494287890327 |
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