Year | Value | 2022 | 50.274715902543 | 2021 | 50.296283101264 | 2020 | 50.325467346013 | 2019 | 50.350747168164 | 2018 | 50.367323739407 | 2017 | 50.379230944105 | 2016 | 50.387716190663 | 2015 | 50.388693474826 | 2014 | 50.385507682458 | 2013 | 50.382804873359 | 2012 | 50.377924494129 | 2011 | 50.371796579854 | 2010 | 50.367065234238 | 2009 | 50.35830695947 | 2008 | 50.341925517678 | 2007 | 50.322535992157 | 2006 | 50.304830373585 | 2005 | 50.294037465433 | 2004 | 50.290632371936 | 2003 | 50.289604108842 | 2002 | 50.287680536155 | 2001 | 50.284671356112 | 2000 | 50.276805748613 | 1999 | 50.265388574524 | 1998 | 50.257277338323 | 1997 | 50.249524814246 | 1996 | 50.241120816836 | 1995 | 50.234045992919 | 1994 | 50.227424332089 | 1993 | 50.219437513327 | 1992 | 50.209438530336 | 1991 | 50.195449328159 | 1990 | 50.180623879318 | 1989 | 50.164312486331 | 1988 | 50.146847887571 | 1987 | 50.130812223839 | 1986 | 50.11567646114 | 1985 | 50.103569753256 | 1984 | 50.095147499479 | 1983 | 50.089016309574 | 1982 | 50.081987761037 | 1981 | 50.075323230767 | 1980 | 50.069975136536 | 1979 | 50.067374078541 | 1978 | 50.0641184165 | 1977 | 50.057043282674 | 1976 | 50.050170597238 | 1975 | 50.044209340005 | 1974 | 50.037670559737 | 1973 | 50.028171993981 | 1972 | 50.016172869621 | 1971 | 50.003047529204 | 1970 | 49.995503863883 | 1969 | 49.989535959831 | 1968 | 49.977262849727 | 1967 | 49.967384925574 | 1966 | 49.959201521397 | 1965 | 49.948566695937 | 1964 | 49.941816109511 | 1963 | 49.933859645373 | 1962 | 49.924582589949 | 1961 | 49.92934779813 | 1960 | 49.9502564267 |
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