Year | Value | 2022 | 32.395 | 2021 | 32.303 | 2020 | 32.242 | 2019 | 32.21 | 2018 | 32.209 | 2017 | 32.237 | 2016 | 32.296 | 2015 | 32.385 | 2014 | 32.504 | 2013 | 32.654 | 2012 | 32.834 | 2011 | 33.015 | 2010 | 33.196 | 2009 | 33.378 | 2008 | 33.56 | 2007 | 33.743 | 2006 | 33.926 | 2005 | 34.11 | 2004 | 34.294 | 2003 | 34.479 | 2002 | 34.585 | 2001 | 34.17 | 2000 | 33.758 | 1999 | 33.347 | 1998 | 32.939 | 1997 | 32.534 | 1996 | 32.132 | 1995 | 31.732 | 1994 | 31.335 | 1993 | 30.94 | 1992 | 30.499 | 1991 | 29.738 | 1990 | 28.988 | 1989 | 28.25 | 1988 | 27.524 | 1987 | 26.809 | 1986 | 26.105 | 1985 | 25.414 | 1984 | 24.736 | 1983 | 24.069 | 1982 | 23.429 | 1981 | 22.895 | 1980 | 22.371 | 1979 | 21.853 | 1978 | 21.345 | 1977 | 20.846 | 1976 | 20.356 | 1975 | 19.873 | 1974 | 19.4 | 1973 | 18.874 | 1972 | 18.36 | 1971 | 17.855 | 1970 | 17.362 | 1969 | 16.88 | 1968 | 16.306 | 1967 | 15.727 | 1966 | 15.165 | 1965 | 14.62 | 1964 | 14.092 | 1963 | 13.578 | 1962 | 13.082 | 1961 | 12.821 | 1960 | 12.608 |
|