Year | Value | 2022 | 50.538813704392 | 2021 | 50.527808583455 | 2020 | 50.518161064791 | 2019 | 50.505937173292 | 2018 | 50.489600855795 | 2017 | 50.4728789948 | 2016 | 50.45504238366 | 2015 | 50.437804322528 | 2014 | 50.423722360034 | 2013 | 50.410854706597 | 2012 | 50.397371922089 | 2011 | 50.382422445473 | 2010 | 50.366585921903 | 2009 | 50.350035663163 | 2008 | 50.333208852728 | 2007 | 50.319561756054 | 2006 | 50.30923697762 | 2005 | 50.302740276329 | 2004 | 50.297367924128 | 2003 | 50.290685155096 | 2002 | 50.283426009823 | 2001 | 50.273001735247 | 2000 | 50.262411716525 | 1999 | 50.253731623223 | 1998 | 50.244530132253 | 1997 | 50.23761727194 | 1996 | 50.237302233081 | 1995 | 50.239387855966 | 1994 | 50.235489886832 | 1993 | 50.229817009342 | 1992 | 50.227972487485 | 1991 | 50.229398755351 | 1990 | 50.225300818133 | 1989 | 50.21223568551 | 1988 | 50.199941966631 | 1987 | 50.18950314119 | 1986 | 50.181117622643 | 1985 | 50.173081372933 | 1984 | 50.158354284398 | 1983 | 50.142163510128 | 1982 | 50.132182523696 | 1981 | 50.12101899788 | 1980 | 50.110681161478 | 1979 | 50.101571997419 | 1978 | 50.091155401083 | 1977 | 50.078954456214 | 1976 | 50.062136633162 | 1975 | 50.040388973901 | 1974 | 50.014608898395 | 1973 | 49.986593506909 | 1972 | 49.959887464182 | 1971 | 49.935187286363 | 1970 | 49.913230810471 | 1969 | 49.906235657161 | 1968 | 49.914938171817 | 1967 | 49.929879433311 | 1966 | 49.933236373227 | 1965 | 49.923619650033 | 1964 | 49.918501863791 | 1963 | 49.914008174676 | 1962 | 49.907779157357 | 1961 | 49.902926599416 | 1960 | 49.898985811673 |
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