Year Percent 1970 -0.02773 1971 -0.00466 1972 -0.00219 1973 -0.12757 1974 -0.07667 1975 -0.33377 1976 0.0076 1977 0.02213 1978 0.00126 1979 0.00426 1980 0.00286 1981 0.01072 1982 0.00568 1983 0.00362 1984 -0.01006 1985 0.00081 1986 0.00414 1987 0.02334 1988 0.00038 1989 0.00407 1990 0.00023 2004 0.81905 2005 1.03153 2006 0.58796 2007 1.09388 2008 1.40996 2009 1.43139 2010 1.00796 2011 1.12086 2012 1.55963 2013 2.18685 2014 2.03786 2015 1.84608 2016 0.08537 2017 -2.54527