Year | Value | 2022 | 27.022 | 2021 | 26.897 | 2020 | 26.786 | 2019 | 26.689 | 2018 | 26.606 | 2017 | 26.538 | 2016 | 26.482 | 2015 | 26.441 | 2014 | 26.414 | 2013 | 26.4 | 2012 | 26.4 | 2011 | 26.4 | 2010 | 26.634 | 2009 | 26.869 | 2008 | 27.105 | 2007 | 27.343 | 2006 | 27.582 | 2005 | 27.822 | 2004 | 28.064 | 2003 | 28.307 | 2002 | 28.518 | 2001 | 28.606 | 2000 | 28.694 | 1999 | 28.782 | 1998 | 28.871 | 1997 | 28.959 | 1996 | 29.048 | 1995 | 29.137 | 1994 | 29.226 | 1993 | 29.315 | 1992 | 29.404 | 1991 | 29.493 | 1990 | 29.583 | 1989 | 29.673 | 1988 | 29.763 | 1987 | 29.853 | 1986 | 29.943 | 1985 | 30.033 | 1984 | 30.124 | 1983 | 30.215 | 1982 | 30.305 | 1981 | 30.396 | 1980 | 30.488 | 1979 | 30.405 | 1978 | 30.295 | 1977 | 30.186 | 1976 | 30.076 | 1975 | 29.967 | 1974 | 29.858 | 1973 | 29.75 | 1972 | 29.641 | 1971 | 29.533 | 1970 | 29.425 | 1969 | 29.369 | 1968 | 29.329 | 1967 | 29.289 | 1966 | 29.249 | 1965 | 29.209 | 1964 | 29.169 | 1963 | 29.129 | 1962 | 29.089 | 1961 | 29.049 | 1960 | 29.009 |
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