Year | Value | 2021 | 17.821 | 2020 | 18.053 | 2019 | 18.35 | 2018 | 18.462 | 2017 | 18.495 | 2016 | 19.002 | 2015 | 19.158 | 2014 | 19.537 | 2013 | 19.9 | 2012 | 20.117 | 2011 | 20.569 | 2010 | 21.379 | 2009 | 22.268 | 2008 | 23.13 | 2007 | 23.978 | 2006 | 24.649 | 2005 | 25.509 | 2004 | 26.586 | 2003 | 27.32 | 2002 | 27.968 | 2001 | 28.49 | 2000 | 28.956 | 1999 | 29.322 | 1998 | 29.79 | 1997 | 30.203 | 1996 | 29.952 | 1995 | 30.453 | 1994 | 31.336 | 1993 | 31.515 | 1992 | 32.354 | 1991 | 33.449 | 1990 | 34.966 | 1989 | 36.184 | 1988 | 36.98 | 1987 | 38.321 | 1986 | 39.412 | 1985 | 40.734 | 1984 | 41.81 | 1983 | 42.813 | 1982 | 44.255 | 1981 | 44.734 | 1980 | 45.083 | 1979 | 45.452 | 1978 | 45.603 | 1977 | 46.051 | 1976 | 46.15 | 1975 | 46.175 | 1974 | 46.676 | 1973 | 46.955 | 1972 | 47.459 | 1971 | 47.608 | 1970 | 47.443 | 1969 | 47.525 | 1968 | 47.578 | 1967 | 47.759 | 1966 | 47.789 | 1965 | 48.152 | 1964 | 48.618 | 1963 | 49.08 | 1962 | 49.566 | 1961 | 49.606 | 1960 | 49.451 |
|