Year | Value | 2021 | 22.940689245799 | 2020 | 22.93914404085 | 2019 | 22.834150764247 | 2018 | 22.924136436442 | 2017 | 22.926768781184 | 2016 | 22.81698633792 | 2015 | 22.753029199883 | 2014 | 22.740074542551 | 2013 | 22.779525882135 | 2012 | 22.745833941306 | 2011 | 22.720890859106 | 2010 | 22.699177558059 | 2009 | 22.643391578955 | 2008 | 22.659224939741 | 2007 | 22.924825591761 | 2006 | 22.875811696769 | 2005 | 22.821060211561 | 2004 | 24.762813291949 | 2003 | 24.661734043551 | 2002 | 24.573809435605 | 2001 | 24.508052864578 | 2000 | 24.426551762461 | 1999 | 24.508921129161 | 1998 | 24.658276529535 | 1997 | 24.547983773872 | 1996 | 24.657679163502 | 1995 | 24.606803489729 | 1994 | 24.59830144294 | 1993 | 24.53850927075 | 1992 | 24.407088743586 | 1991 | 24.197133106118 | 1990 | 23.976628632819 | 1989 | 23.966047381777 | 1988 | 24.014461814881 | 1987 | 23.917216181673 | 1986 | 23.845763794988 | 1985 | 23.840785744716 | 1984 | 23.800447329913 | 1983 | 23.717369459314 | 1982 | 23.634780132254 | 1981 | 23.542426880545 | 1980 | 23.970122436883 | 1979 | 24.108581695593 | 1978 | 23.975679330209 | 1977 | 24.013535665994 | 1976 | 24.026964824865 | 1975 | 23.993391927686 | 1974 | 24.103950951155 | 1973 | 24.091447941171 | 1972 | 24.035536168262 | 1971 | 23.800063903977 | 1970 | 23.552088687607 | 1969 | 23.465494167604 | 1968 | 23.385151123645 | 1967 | 23.347758035462 | 1966 | 23.272508786797 | 1965 | 23.273550699471 | 1964 | 23.242756391555 | 1963 | 23.234421090165 | 1962 | 23.203858318399 | 1961 | 23.214161677063 |
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