Year | Value | 2021 | 20.298 | 2020 | 20.473 | 2019 | 20.828 | 2018 | 20.77 | 2017 | 20.958 | 2016 | 21.139 | 2015 | 21.31 | 2014 | 21.423 | 2013 | 21.502 | 2012 | 21.544 | 2011 | 21.621 | 2010 | 21.705 | 2009 | 21.832 | 2008 | 22.031 | 2007 | 22.295 | 2006 | 22.608 | 2005 | 22.994 | 2004 | 23.426 | 2003 | 23.9 | 2002 | 24.516 | 2001 | 25.149 | 2000 | 25.772 | 1999 | 26.357 | 1998 | 26.893 | 1997 | 27.337 | 1996 | 27.752 | 1995 | 28.135 | 1994 | 28.382 | 1993 | 28.598 | 1992 | 28.731 | 1991 | 28.717 | 1990 | 29.117 | 1989 | 29.515 | 1988 | 29.851 | 1987 | 30.092 | 1986 | 30.405 | 1985 | 30.773 | 1984 | 31.091 | 1983 | 31.257 | 1982 | 31.247 | 1981 | 31.098 | 1980 | 30.774 | 1979 | 31.226 | 1978 | 31.55 | 1977 | 31.924 | 1976 | 32.401 | 1975 | 32.936 | 1974 | 33.575 | 1973 | 34.235 | 1972 | 34.653 | 1971 | 35.126 | 1970 | 35.939 | 1969 | 36.49 | 1968 | 37.057 | 1967 | 37.776 | 1966 | 38.448 | 1965 | 39.092 | 1964 | 39.745 | 1963 | 40.452 | 1962 | 41.176 | 1961 | 41.9 | 1960 | 42.615 |
|