Year | Value | 2022 | 18.378783455959 | 2021 | 18.622986713 | 2020 | 18.865430001843 | 2019 | 19.111144402383 | 2018 | 19.349291834188 | 2017 | 19.585546872379 | 2016 | 19.834216878144 | 2015 | 20.089919322862 | 2014 | 20.350403922227 | 2013 | 20.613665785429 | 2012 | 20.879491189983 | 2011 | 21.151059316147 | 2010 | 21.430950391377 | 2009 | 21.706867360646 | 2008 | 21.989989739524 | 2007 | 22.280313098105 | 2006 | 22.577047091036 | 2005 | 22.877544989381 | 2004 | 23.180869166754 | 2003 | 23.488976697058 | 2002 | 23.810074912869 | 2001 | 24.139274858065 | 2000 | 24.497632304165 | 1999 | 24.946596022865 | 1998 | 25.400860735697 | 1997 | 25.871558298072 | 1996 | 26.347559486604 | 1995 | 26.814759637187 | 1994 | 27.303841906827 | 1993 | 27.797803097384 | 1992 | 28.285489873401 | 1991 | 28.784949233965 | 1990 | 29.307268226478 | 1989 | 29.865407639513 | 1988 | 30.438778386983 | 1987 | 31.023789859352 | 1986 | 31.617724277792 | 1985 | 32.224222444776 | 1984 | 32.846360623455 | 1983 | 33.476073426817 | 1982 | 34.113620881173 | 1981 | 34.772188097924 | 1980 | 35.464725544027 | 1979 | 36.174895174822 | 1978 | 36.88721107938 | 1977 | 37.606539776335 | 1976 | 38.328031448196 | 1975 | 39.049655870836 | 1974 | 39.775416590831 | 1973 | 40.501750293052 | 1972 | 41.233499479749 | 1971 | 41.98778349843 | 1970 | 42.748931996848 | 1969 | 43.504720706544 | 1968 | 44.266571973482 | 1967 | 45.032961421281 | 1966 | 45.798411171409 | 1965 | 46.564737102181 | 1964 | 47.331393937179 | 1963 | 48.152693375922 | 1962 | 48.969134593987 | 1961 | 49.782402546576 | 1960 | 50.583070455523 |
|