Year | Value | 2021 | 2.1336042672085 | 2020 | 2.1336042672085 | 2019 | 2.1336042672085 | 2018 | 2.1336042672085 | 2017 | 2.1336042672085 | 2016 | 2.1336042672085 | 2015 | 2.1336042672085 | 2014 | 2.1336042672085 | 2013 | 2.1336042672085 | 2012 | 2.1336042672085 | 2011 | 2.1336042672085 | 2010 | 2.1336042672085 | 2009 | 2.1336042672085 | 2008 | 2.1336042672085 | 2007 | 2.1336042672085 | 2006 | 2.1336042672085 | 2005 | 2.1336042672085 | 2004 | 2.1241214122428 | 2003 | 2.1146390652781 | 2002 | 2.1051562103124 | 2001 | 2.0956733553467 | 2000 | 2.086191008382 | 1999 | 2.0767081534163 | 1998 | 2.0672252984506 | 1997 | 2.0577429514859 | 1996 | 2.0482600965202 | 1995 | 2.0387772415545 | 1994 | 2.0292948945898 | 1993 | 2.0198120396241 | 1992 | 2.0103291846584 | 1991 | 2.0008468376937 | 1990 | 1.991363982728 | 1989 | 1.9818811277623 | 1988 | 1.9723987807976 | 1987 | 1.9629159258319 | 1986 | 1.9534330708661 | 1985 | 1.9439507239014 | 1984 | 1.9344678689357 | 1983 | 1.92498501397 | 1982 | 1.9155026670053 | 1981 | 1.9060198120396 | 1980 | 1.8965369570739 | 1979 | 1.8870546101092 | 1978 | 1.8775717551435 | 1977 | 1.8680889001778 | 1976 | 1.8586065532131 | 1975 | 1.8491236982474 | 1974 | 1.8402724823344 | 1973 | 1.8402724823344 | 1972 | 1.8301052310508 | 1971 | 1.8301052310508 | 1970 | 1.8301052310508 | 1969 | 1.8046871028417 | 1968 | 1.8046871028417 | 1967 | 1.8046871028417 | 1966 | 1.8046871028417 | 1965 | 1.7792689746327 | 1964 | 1.7792689746327 | 1963 | 1.7792689746327 | 1962 | 1.7792689746327 | 1961 | 1.7792689746327 |
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