Year Measure 1971 0.0117 1972 0.00965 1973 0.01048 1974 0.01168 1975 0.00581 1976 0.0039 1977 0.00801 1978 0.01273 1979 0.01936 1980 0.01747 1981 0.00993 1982 0.0081 1983 0.01419 1984 0.01515 1985 0.02015 1986 0.02092 1987 0.01903 1988 0.02157 1989 0.0233 1990 0.02657 1991 0.02014 1992 0.02214 1993 0.02337 1994 0.02198 1995 0.02206 1996 0.02796 1997 0.02104 1998 0.02291 1999 0.0257 2000 0.01701 2001 0.01678 2002 0.01635 2003 0.02098 2004 0.0198 2005 0.02372 2006 0.02777 2007 0.02451 2008 0.02859 2009 0.02101 2010 0.02893