Year | Value | 2022 | 12.25 | 2021 | 12.956 | 2020 | 13.724 | 2019 | 14.557 | 2018 | 15.461 | 2017 | 16.44 | 2016 | 17.5 | 2015 | 18.65 | 2014 | 19.855 | 2013 | 21.118 | 2012 | 22.436 | 2011 | 23.817 | 2010 | 24.839 | 2009 | 25.376 | 2008 | 25.92 | 2007 | 26.473 | 2006 | 27.033 | 2005 | 27.6 | 2004 | 28.173 | 2003 | 28.491 | 2002 | 28.471 | 2001 | 28.451 | 2000 | 28.431 | 1999 | 28.411 | 1998 | 28.391 | 1997 | 28.371 | 1996 | 28.351 | 1995 | 28.331 | 1994 | 28.312 | 1993 | 28.956 | 1992 | 30.553 | 1991 | 32.204 | 1990 | 33.898 | 1989 | 35.634 | 1988 | 37.406 | 1987 | 39.217 | 1986 | 41.056 | 1985 | 42.921 | 1984 | 44.803 | 1983 | 46.706 | 1982 | 48.615 | 1981 | 50.529 | 1980 | 52.438 | 1979 | 54.346 | 1978 | 56.238 | 1977 | 58.112 | 1976 | 59.961 | 1975 | 61.787 | 1974 | 63.577 | 1973 | 65.331 | 1972 | 67.042 | 1971 | 68.713 | 1970 | 70.335 | 1969 | 71.907 | 1968 | 73.425 | 1967 | 74.894 | 1966 | 76.306 | 1965 | 77.662 | 1964 | 78.96 | 1963 | 80.206 | 1962 | 81.393 | 1961 | 82.525 | 1960 | 83.6 |
|