Year | Value | 2022 | 50.096331393774 | 2021 | 50.086663006818 | 2020 | 50.072881518277 | 2019 | 50.056165586858 | 2018 | 50.036794377675 | 2017 | 50.015663832173 | 2016 | 49.993095078767 | 2015 | 49.969015208662 | 2014 | 49.943183338352 | 2013 | 49.915159287323 | 2012 | 49.88565098055 | 2011 | 49.858302883498 | 2010 | 49.834972701893 | 2009 | 49.811393037939 | 2008 | 49.786172275455 | 2007 | 49.754497146718 | 2006 | 49.717868129637 | 2005 | 49.706377841169 | 2004 | 49.695638284316 | 2003 | 49.661061561456 | 2002 | 49.627202516543 | 2001 | 49.594324269649 | 2000 | 49.564355532984 | 1999 | 49.533238792332 | 1998 | 49.498548263315 | 1997 | 49.456429330333 | 1996 | 49.407481793593 | 1995 | 49.361722818333 | 1994 | 49.325893229456 | 1993 | 49.282839082742 | 1992 | 49.238517946314 | 1991 | 49.20877317144 | 1990 | 49.179815635544 | 1989 | 49.15131092761 | 1988 | 49.123338239896 | 1987 | 49.099180662291 | 1986 | 49.078565587331 | 1985 | 49.058456603746 | 1984 | 49.041525062484 | 1983 | 49.025248793847 | 1982 | 49.00378232457 | 1981 | 48.97800850372 | 1980 | 48.950544074906 | 1979 | 48.922461026355 | 1978 | 48.891715450984 | 1977 | 48.85372825927 | 1976 | 48.807468885184 | 1975 | 48.756105523333 | 1974 | 48.700411598424 | 1973 | 48.640631100149 | 1972 | 48.577370225902 | 1971 | 48.511048345395 | 1970 | 48.441892240072 | 1969 | 48.369223474807 | 1968 | 48.297128998924 | 1967 | 48.224749177052 | 1966 | 48.149099095545 | 1965 | 48.070302279773 | 1964 | 47.987223802036 | 1963 | 47.90305987456 | 1962 | 47.817338667074 | 1961 | 47.728181384877 | 1960 | 47.638443742825 |
|