Year | Value | 2021 | 27.207 | 2020 | 27.645 | 2019 | 28.064 | 2018 | 28.46 | 2017 | 28.616 | 2016 | 28.86 | 2015 | 29.188 | 2014 | 29.547 | 2013 | 30.075 | 2012 | 30.544 | 2011 | 30.995 | 2010 | 30.783 | 2009 | 30.578 | 2008 | 30.398 | 2007 | 29.88 | 2006 | 29.26 | 2005 | 28.821 | 2004 | 28.583 | 2003 | 28.272 | 2002 | 29.025 | 2001 | 29.87 | 2000 | 30.702 | 1999 | 31.46 | 1998 | 32.239 | 1997 | 32.878 | 1996 | 33.519 | 1995 | 33.658 | 1994 | 34.216 | 1993 | 34.784 | 1992 | 35.559 | 1991 | 36.276 | 1990 | 36.577 | 1989 | 37.061 | 1988 | 37.42 | 1987 | 37.776 | 1986 | 38.02 | 1985 | 38.093 | 1984 | 37.752 | 1983 | 37.467 | 1982 | 37.214 | 1981 | 36.75 | 1980 | 36.261 | 1979 | 35.751 | 1978 | 35.317 | 1977 | 34.928 | 1976 | 34.553 | 1975 | 34.509 | 1974 | 34.582 | 1973 | 34.691 | 1972 | 35.143 | 1971 | 35.791 | 1970 | 36.768 | 1969 | 37.777 | 1968 | 39.191 | 1967 | 40.585 | 1966 | 41.895 | 1965 | 42.173 | 1964 | 42.465 | 1963 | 42.993 | 1962 | 43.541 | 1961 | 44.099 | 1960 | 43.841 |
|