Year | Value | 2022 | 53.078967961701 | 2021 | 53.061066956789 | 2020 | 53.029279162717 | 2019 | 52.933686730867 | 2018 | 52.84036184832 | 2017 | 52.743071268961 | 2016 | 52.63751659518 | 2015 | 52.523490871027 | 2014 | 52.401736605938 | 2013 | 52.273439685595 | 2012 | 52.140310175954 | 2011 | 52.047887664338 | 2010 | 52.02611892761 | 2009 | 52.031321072297 | 2008 | 52.040307123496 | 2007 | 52.045291366697 | 2006 | 52.038903047246 | 2005 | 52.033588542402 | 2004 | 52.031526994148 | 2003 | 52.029368715313 | 2002 | 52.025619071976 | 2001 | 52.000582981495 | 2000 | 51.946533424713 | 1999 | 51.88006147801 | 1998 | 51.814812692227 | 1997 | 51.75831916444 | 1996 | 51.704811067111 | 1995 | 51.651493415961 | 1994 | 51.597694319909 | 1993 | 51.54079724306 | 1992 | 51.483739291565 | 1991 | 51.396285769475 | 1990 | 51.257327390521 | 1989 | 51.093568430289 | 1988 | 50.915932667238 | 1987 | 50.721277196223 | 1986 | 50.508696421595 | 1985 | 50.274939172749 | 1984 | 50.018981094829 | 1983 | 49.741411364379 | 1982 | 49.439405980708 | 1981 | 49.144132370977 | 1980 | 48.974043337192 | 1979 | 48.913906475845 | 1978 | 48.85957211601 | 1977 | 48.809480327104 | 1976 | 48.75963366726 | 1975 | 48.709090835456 | 1974 | 48.657392429634 | 1973 | 48.606751184241 | 1972 | 48.555710603252 | 1971 | 48.504595087899 | 1970 | 48.565212468255 | 1969 | 48.735525089844 | 1968 | 48.899020731639 | 1967 | 49.057299323565 | 1966 | 49.216045518156 | 1965 | 49.379294526897 | 1964 | 49.5540768696 | 1963 | 49.744341951678 | 1962 | 49.954041894442 | 1961 | 50.181337870511 | 1960 | 50.198854327906 |
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