Year | Value | 2022 | 49.399743788516 | 2021 | 49.378355188658 | 2020 | 49.353946878407 | 2019 | 49.323071939362 | 2018 | 49.298704049358 | 2017 | 49.287823122948 | 2016 | 49.258523611807 | 2015 | 49.204431033383 | 2014 | 49.152787808777 | 2013 | 49.116682575297 | 2012 | 49.090490930804 | 2011 | 49.124032906861 | 2010 | 49.167943625281 | 2009 | 49.175520043345 | 2008 | 49.191265130363 | 2007 | 49.212889834099 | 2006 | 49.226106741438 | 2005 | 49.077884051109 | 2004 | 48.763116997561 | 2003 | 48.431478784211 | 2002 | 48.087663907783 | 2001 | 47.734194403398 | 2000 | 47.371958896483 | 1999 | 47.15055245178 | 1998 | 47.0748220926 | 1997 | 46.996662414281 | 1996 | 46.922054594273 | 1995 | 46.853168867602 | 1994 | 46.789409682123 | 1993 | 46.729241337127 | 1992 | 46.667761574147 | 1991 | 46.598629977031 | 1990 | 46.522513779262 | 1989 | 46.440835226373 | 1988 | 46.354715141991 | 1987 | 46.264064956023 | 1986 | 46.173742339038 | 1985 | 46.092419400849 | 1984 | 46.02441768898 | 1983 | 46.070150882465 | 1982 | 46.231048211629 | 1981 | 46.402925435771 | 1980 | 46.584962466922 | 1979 | 46.77347610881 | 1978 | 46.969620536023 | 1977 | 47.177930643775 | 1976 | 47.401315789474 | 1975 | 47.642048466713 | 1974 | 47.872716277439 | 1973 | 47.870319193036 | 1972 | 47.750740760614 | 1971 | 47.774010376241 | 1970 | 47.838414143895 | 1969 | 47.9203874979 | 1968 | 48.021455507414 | 1967 | 48.140536990787 | 1966 | 48.278252313012 | 1965 | 48.396479678508 | 1964 | 48.415291549795 | 1963 | 48.394866180323 | 1962 | 48.41869593794 | 1961 | 48.454313073115 | 1960 | 48.49185626208 |
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