Year Measure 1960 0.01421 1961 0.01396 1962 0.01324 1963 0.01288 1964 0.01264 1965 0.01614 1966 0.01776 1967 0.01709 1968 0.01734 1969 0.01448 1970 0.01928 1971 0.01476 1972 0.01445 1973 0.01666 1974 0.01928 1975 0.01864 1976 0.01514 1977 0.01922 1978 0.0201 1979 0.02015 1980 0.02094 1981 0.02191 1982 0.02177 1983 0.02067 1984 0.02045 1985 0.01923 1986 0.02052 1987 0.02242 1988 0.02205 1989 0.01992 1990 0.01894 1991 0.01607 1992 0.01863 1993 0.019 1994 0.02103 1995 0.02286 1996 0.02297 1997 0.01813 1998 0.01798 1999 0.02052 2000 0.02269 2001 0.02373 2002 0.02412 2003 0.02008 2004 0.02196 2005 0.0204 2006 0.02076 2007 0.02178 2008 0.02183 2009 0.01947 2010 0.02134 2011 0.01923