Year Age 1970 1.1 1971 1.1 1972 1.2 1973 1.3 1974 1.4 1975 1.4 1976 1.5 1977 1.6 1978 1.7 1979 1.8 1980 1.9 1981 2 1982 2.2 1983 2.3 1984 2.4 1985 2.6 1986 2.7 1987 2.8 1988 3 1989 3.1 1990 3.3 1991 3.4 1992 3.6 1993 3.7 1994 3.9 1995 4 1996 4.2 1997 4.3 1998 4.5 1999 4.6 2000 4.8 2001 4.9 2002 5.1 2003 5.3 2004 5.4 2005 5.6 2006 5.7 2007 5.9 2008 6 2009 6.2