Year | Value | 2021 | 9.2689933386959 | 2020 | 9.6370980504976 | 2019 | 9.9095921741538 | 2018 | 10.176548130223 | 2017 | 10.37061863823 | 2016 | 10.134696666353 | 2015 | 9.8884699934686 | 2014 | 9.9346694151868 | 2013 | 9.638321929539 | 2012 | 9.9766331970043 | 2011 | 9.9732227860842 | 2010 | 10.544200781857 | 2009 | 10.782550863438 | 2008 | 10.745055990091 | 2007 | 10.207634861063 | 2006 | 9.9584984696539 | 2005 | 9.7606738408835 | 2004 | 9.499468536744 | 2003 | 9.2841786787417 | 2002 | 9.2770376943005 | 2001 | 9.4368921938271 | 2000 | 9.7709274341918 | 1999 | 9.7122238893736 | 1998 | 9.8328194185302 | 1997 | 10.123500604033 | 1996 | 10.32663227367 | 1995 | 10.517434814963 | 1994 | 11.326632862636 | 1993 | 11.818651208788 | 1992 | 12.277059682638 | 1991 | 13.011285691276 | 1990 | 13.54862721053 | 1989 | 14.245510046602 | 1988 | 14.770034924689 | 1987 | 15.046032569959 | 1986 | 15.431044300396 | 1985 | 15.779058395694 | 1984 | 16.005408942696 | 1983 | 16.082452858223 | 1982 | 16.256524981161 | 1981 | 16.558396701253 | 1980 | 17.180091619105 | 1979 | 17.725439148729 | 1978 | 17.807763242013 | 1977 | 18.13288611712 | 1976 | 18.448877612129 | 1975 | 18.443529577529 | 1974 | 18.455475132038 | 1973 | 17.35087072561 | 1972 | 17.023717419627 | 1971 | 17.007328643641 | 1970 | 17.096590185694 | 1969 | 17.451755054401 | 1968 | 18.01930362036 | 1967 | 17.940059685746 | 1966 | 15.563001189146 | 1965 | 15.936753596893 | 1964 | 16.504625094473 | 1963 | 16.994221610107 | 1962 | 17.204125178699 | 1961 | 18.10795587029 | 1960 | 19.117433708391 |
|