Year | Value | 2021 | 12.781893004115 | 2020 | 12.844993141289 | 2019 | 12.935528120713 | 2018 | 13.020576131687 | 2017 | 13.108367626886 | 2016 | 13.20438957476 | 2015 | 13.294924554184 | 2014 | 13.360768175583 | 2013 | 13.421124828532 | 2012 | 13.456790123457 | 2011 | 13.495198902606 | 2010 | 13.588477366255 | 2009 | 13.647736625514 | 2008 | 13.715226337449 | 2007 | 13.790946502058 | 2006 | 13.863923182442 | 2005 | 13.936899862826 | 2004 | 14.019204389575 | 2003 | 14.101508916324 | 2002 | 14.197530864197 | 2001 | 14.301783264746 | 2000 | 14.42524005487 | 1999 | 14.598079561042 | 1998 | 14.748971193416 | 1997 | 14.916323731138 | 1996 | 15.089163237311 | 1995 | 15.255074053758 | 1994 | 15.42786615469 | 1993 | 15.595172792101 | 1992 | 15.732309380143 | 1991 | 15.863960504663 | 1990 | 15.995611629183 | 1989 | 16.121777290181 | 1988 | 16.25068568294 | 1987 | 16.341195831048 | 1986 | 16.410748560461 | 1985 | 16.500274273176 | 1984 | 16.569783383603 | 1983 | 16.572910977608 | 1982 | 16.641179683233 | 1981 | 16.705786026201 | 1980 | 16.794976794977 | 1979 | 16.855895196507 | 1978 | 16.943231441048 | 1977 | 17.030567685589 | 1976 | 17.115961800819 | 1975 | 17.25238744884 | 1974 | 17.394980905619 | 1973 | 17.517730496454 | 1972 | 17.65139116203 | 1971 | 17.842923370603 | 1970 | 18.260158167439 | 1969 | 18.140169075539 | 1968 | 18.535587673848 | 1967 | 18.647395691301 | 1966 | 18.805563130624 | 1965 | 19.100081810744 | 1964 | 19.170984455959 | 1963 | 19.143714207799 | 1962 | 19.416416689392 | 1961 | 19.389146441233 |
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