Year | Value | 2022 | 49.341672978973 | 2021 | 49.347735361377 | 2020 | 49.370006721471 | 2019 | 49.362043625992 | 2018 | 49.331584802279 | 2017 | 49.304929411679 | 2016 | 49.279568831889 | 2015 | 49.24722308962 | 2014 | 49.204445137899 | 2013 | 49.156459664269 | 2012 | 49.10714963435 | 2011 | 49.055830026539 | 2010 | 49.002078768008 | 2009 | 48.949244420935 | 2008 | 48.861550434593 | 2007 | 48.738000527347 | 2006 | 48.616094775596 | 2005 | 48.495587632363 | 2004 | 48.3769712689 | 2003 | 48.282811738906 | 2002 | 48.211595452386 | 2001 | 48.140399996474 | 2000 | 48.070293078295 | 1999 | 48.012312365356 | 1998 | 48.024187250096 | 1997 | 48.093645785951 | 1996 | 48.163962188932 | 1995 | 48.236719721447 | 1994 | 48.30837343452 | 1993 | 48.332535971402 | 1992 | 48.311745470369 | 1991 | 48.280778592745 | 1990 | 48.234505985323 | 1989 | 48.187354960774 | 1988 | 48.134448656969 | 1987 | 48.098927682913 | 1986 | 48.089754972338 | 1985 | 48.080245068305 | 1984 | 48.075340570809 | 1983 | 48.08036638738 | 1982 | 48.094760855007 | 1981 | 48.114630397663 | 1980 | 48.139184027723 | 1979 | 48.164456374952 | 1978 | 48.226422035371 | 1977 | 48.33226641682 | 1976 | 48.434462939811 | 1975 | 48.460323793437 | 1974 | 48.419439627773 | 1973 | 48.377754485243 | 1972 | 48.333973909942 | 1971 | 48.289529916655 | 1970 | 48.241789373782 | 1969 | 48.189787115625 | 1968 | 48.135668797026 | 1967 | 48.077269786729 | 1966 | 48.010455863241 | 1965 | 47.937775990009 | 1964 | 47.858558584437 | 1963 | 47.7697860357 | 1962 | 47.673693361944 | 1961 | 47.571152953498 | 1960 | 47.464906072491 |
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