Year | Value | 2021 | 56.232 | 2020 | 58.129 | 2019 | 58.644 | 2018 | 58.968 | 2017 | 58.208 | 2016 | 57.956 | 2015 | 57.32 | 2014 | 56.637 | 2013 | 55.186 | 2012 | 53.355 | 2011 | 51.103 | 2010 | 48.948 | 2009 | 46.644 | 2008 | 45.61 | 2007 | 44.863 | 2006 | 44.291 | 2005 | 43.925 | 2004 | 43.499 | 2003 | 42.855 | 2002 | 43.334 | 2001 | 41.473 | 2000 | 42.941 | 1999 | 43.068 | 1998 | 44.449 | 1997 | 45.707 | 1996 | 46.73 | 1995 | 47.978 | 1994 | 49.987 | 1993 | 51.795 | 1992 | 53.659 | 1991 | 55.325 | 1990 | 56.389 | 1989 | 57.3 | 1988 | 58.337 | 1987 | 58.706 | 1986 | 59.161 | 1985 | 58.972 | 1984 | 58.628 | 1983 | 57.797 | 1982 | 57.548 | 1981 | 57.002 | 1980 | 56.62 | 1979 | 50.392 | 1978 | 49.932 | 1977 | 53.19 | 1976 | 54.419 | 1975 | 55.639 | 1974 | 55.516 | 1973 | 55.393 | 1972 | 55.616 | 1971 | 55.411 | 1970 | 55.268 | 1969 | 54.941 | 1968 | 54.552 | 1967 | 54.302 | 1966 | 53.947 | 1965 | 53.537 | 1964 | 53.081 | 1963 | 52.639 | 1962 | 52.142 | 1961 | 51.692 | 1960 | 51.251 |
|