Year | Value | 2022 | 48.699472408577 | 2021 | 48.650464610243 | 2020 | 48.605182615869 | 2019 | 48.561504796551 | 2018 | 48.522019716379 | 2017 | 48.489905997593 | 2016 | 48.594576319274 | 2015 | 48.598990731417 | 2014 | 48.421162819333 | 2013 | 48.328148234936 | 2012 | 48.266768410888 | 2011 | 48.202336522331 | 2010 | 48.136612972722 | 2009 | 48.07414403443 | 2008 | 48.012851054384 | 2007 | 47.947959694611 | 2006 | 47.879178099884 | 2005 | 47.806317654514 | 2004 | 47.731584377986 | 2003 | 47.657908124489 | 2002 | 47.589300247575 | 2001 | 47.528989906651 | 2000 | 47.468119400172 | 1999 | 47.400367102709 | 1998 | 47.333609060039 | 1997 | 47.268833633565 | 1996 | 47.365402446482 | 1995 | 47.653635181527 | 1994 | 47.945813604156 | 1993 | 48.251996922313 | 1992 | 48.583403245463 | 1991 | 48.737219775268 | 1990 | 48.705603174918 | 1989 | 48.644370726451 | 1988 | 48.570843983368 | 1987 | 48.492340653134 | 1986 | 48.411162803287 | 1985 | 48.913129525454 | 1984 | 49.855916742713 | 1983 | 50.606075422273 | 1982 | 51.22775572258 | 1981 | 51.704458646424 | 1980 | 51.851065192452 | 1979 | 51.694733814466 | 1978 | 51.512685712159 | 1977 | 51.302408492286 | 1976 | 51.16480553468 | 1975 | 51.080973656414 | 1974 | 50.959268838047 | 1973 | 50.8201882226 | 1972 | 50.671293343501 | 1971 | 50.536012922509 | 1970 | 50.507271315047 | 1969 | 50.581960719702 | 1968 | 50.665075575258 | 1967 | 50.755028850831 | 1966 | 50.84844589662 | 1965 | 50.945119958656 | 1964 | 51.04568879042 | 1963 | 51.148525832333 | 1962 | 51.254309728436 | 1961 | 51.359589684525 | 1960 | 51.46630770934 |
|