Year | Value | 2023 | 50.066124863887 | 2022 | 50.042915984099 | 2021 | 50.010145207222 | 2020 | 49.973998652506 | 2019 | 49.944009133051 | 2018 | 49.923502624527 | 2017 | 49.908519317655 | 2016 | 49.892732687987 | 2015 | 49.87680815659 | 2014 | 49.861990892068 | 2013 | 49.847017194907 | 2012 | 49.829733684628 | 2011 | 49.80951005416 | 2010 | 49.812515940545 | 2009 | 49.840245300728 | 2008 | 49.867711842119 | 2007 | 49.872071026068 | 2006 | 49.85281035576 | 2005 | 49.833700798059 | 2004 | 49.815090157589 | 2003 | 49.796725659168 | 2002 | 49.778625405891 | 2001 | 49.760879018907 | 2000 | 49.743733229326 | 1999 | 49.726973598959 | 1998 | 49.708577236874 | 1997 | 49.687357634006 | 1996 | 49.663538039513 | 1995 | 49.637570993409 | 1994 | 49.615344413696 | 1993 | 49.597337535291 | 1992 | 49.578414377429 | 1991 | 49.559215930388 | 1990 | 49.539802526891 | 1989 | 49.519660339152 | 1988 | 49.498397558907 | 1987 | 49.475735683682 | 1986 | 49.451403586852 | 1985 | 49.424554938666 | 1984 | 49.395163640992 | 1983 | 49.363903057689 | 1982 | 49.330989058473 | 1981 | 49.296167708641 | 1980 | 49.257736647439 | 1979 | 49.17606163715 | 1978 | 49.050592061378 | 1977 | 48.91929305989 | 1976 | 48.780879038501 | 1975 | 48.751307056342 |
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