Year | Value | 2021 | 76.976723171153 | 2020 | 77.463516850857 | 2019 | 79.141712376034 | 2018 | 78.965781298422 | 2017 | 78.872476168734 | 2016 | 78.879724269494 | 2015 | 79.0036457097 | 2014 | 79.136284319931 | 2013 | 79.041712762615 | 2012 | 79.032883912637 | 2011 | 78.923970442997 | 2010 | 78.817196495134 | 2009 | 78.654855879109 | 2008 | 78.303770149918 | 2007 | 78.239607348359 | 2006 | 77.968794265324 | 2005 | 77.746065301032 | 2004 | 77.734790675 | 2003 | 77.300419530223 | 2002 | 77.192299271498 | 2001 | 77.088596040168 | 2000 | 76.885154425386 | 1999 | 76.805024000892 | 1998 | 76.7824593496 | 1997 | 76.625562809285 | 1996 | 76.244440160203 | 1995 | 75.855506968242 | 1994 | 75.842643462985 | 1993 | 75.646421497128 | 1992 | 75.837837408923 | 1991 | 75.587951671753 | 1990 | 75.43630625793 | 1989 | 75.226626868046 | 1988 | 74.972530510776 | 1987 | 74.963739944202 | 1986 | 74.795633078467 | 1985 | 74.73592873825 | 1984 | 74.736595876091 | 1983 | 74.619627600696 | 1982 | 74.494247552343 | 1981 | 74.154897134414 | 1980 | 73.755031317467 | 1979 | 73.907809346708 | 1978 | 73.470037138845 | 1977 | 73.349134015993 | 1976 | 72.952963980482 | 1975 | 72.693588199144 | 1974 | 72.079667745495 | 1973 | 71.529529583723 | 1972 | 71.325953893466 | 1971 | 71.290476850232 | 1970 | 70.985282370519 | 1969 | 70.694165012902 | 1968 | 70.175848866992 | 1967 | 70.713823203894 | 1966 | 70.376434003575 | 1965 | 70.366476175408 | 1964 | 70.312586527797 | 1963 | 70.048950715753 | 1962 | 70.231254355798 | 1961 | 70.366608057054 | 1960 | 69.892995307874 |
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