Year | Value | 2021 | 1.822 | 2020 | 1.905 | 2019 | 1.916 | 2018 | 1.996 | 2017 | 2.041 | 2016 | 2.086 | 2015 | 2.137 | 2014 | 2.211 | 2013 | 2.269 | 2012 | 2.294 | 2011 | 2.317 | 2010 | 2.34 | 2009 | 2.364 | 2008 | 2.391 | 2007 | 2.421 | 2006 | 2.456 | 2005 | 2.495 | 2004 | 2.536 | 2003 | 2.579 | 2002 | 2.623 | 2001 | 2.669 | 2000 | 2.716 | 1999 | 2.766 | 1998 | 2.8 | 1997 | 2.869 | 1996 | 2.956 | 1995 | 3.038 | 1994 | 3.127 | 1993 | 3.216 | 1992 | 3.292 | 1991 | 3.367 | 1990 | 3.45 | 1989 | 3.55 | 1988 | 3.65 | 1987 | 3.803 | 1986 | 3.971 | 1985 | 4.087 | 1984 | 4.184 | 1983 | 4.291 | 1982 | 4.443 | 1981 | 4.604 | 1980 | 4.776 | 1979 | 4.998 | 1978 | 5.254 | 1977 | 5.414 | 1976 | 5.603 | 1975 | 5.791 | 1974 | 6.004 | 1973 | 6.177 | 1972 | 6.318 | 1971 | 6.442 | 1970 | 6.551 | 1969 | 6.649 | 1968 | 6.707 | 1967 | 6.753 | 1966 | 6.79 | 1965 | 6.819 | 1964 | 6.833 | 1963 | 6.817 | 1962 | 6.8 | 1961 | 6.777 | 1960 | 6.763 |
|