Year | Value | 2021 | 10.3 | 2020 | 10.6 | 2019 | 10.2 | 2018 | 10.2 | 2017 | 10.7 | 2016 | 10.4 | 2015 | 10.1 | 2014 | 10.6 | 2013 | 10.9 | 2012 | 11.5 | 2011 | 11.7 | 2010 | 12 | 2009 | 12.3 | 2008 | 13.2 | 2007 | 13.7 | 2006 | 14.3 | 2005 | 15.3 | 2004 | 15.7 | 2003 | 15.9 | 2002 | 16.6 | 2001 | 16.5 | 2000 | 17 | 1999 | 17.3 | 1998 | 16.7 | 1997 | 17.4 | 1996 | 18.3 | 1995 | 18.3 | 1994 | 19.6 | 1993 | 20.3 | 1992 | 21.1 | 1991 | 20.7 | 1990 | 21.3 | 1989 | 20.8 | 1988 | 20.1 | 1987 | 19.3 | 1986 | 18.6 | 1985 | 19 | 1984 | 20.1 | 1983 | 21 | 1982 | 22.6 | 1981 | 25.5 | 1980 | 27.2 | 1979 | 27.5 | 1978 | 27.1 | 1977 | 26 | 1976 | 25.8 | 1975 | 25.3 | 1974 | 27.3 | 1973 | 23 | 1972 | 25.3 | 1971 | 26.1 | 1970 | 27.5 | 1969 | 27.7 | 1968 | 31.6 | 1967 | 31 | 1966 | 36 | 1965 | 36 | 1964 | 38.9 | 1963 | 40.4 | 1962 | 38.8 | 1961 | 39.7 | 1960 | 40.432 |
|