Year Percent 1966 4.14706 1967 2.52991 1968 0.44509 1969 0.73471 1970 0.28572 1971 1.19445 1972 3.45864 1973 2.30811 1974 2.85729 1975 0.59553 1976 2.766 1977 4.55347 1978 3.23534 1979 -5.96412 1980 -13.30041 1981 -11.88707 1982 -7.7007 1983 0.11178 1984 -0.0319 1985 -0.71835 1986 -1.11762 1987 1.19972 1988 0.57746 1989 -0.3404 1990 3.45426 1991 0.1287 1992 5.55805 1993 4.39512 1994 3.35033 1995 3.49986 1996 -0.26321 1997 2.12966 1998 1.74907 1999 1.34535 2000 0.39464 2001 0.22252 2002 0.99362 2003 1.03105 2004 0.39918 2005 2.2273 2006 3.86882 2007 1.40855 2008 1.67886 2009 -2.51376 2010 1.65321 2011 3.34353 2012 2.34 2013 1.89154 2014 1.4855 2015 1.87017 2016 2.05926 2017 1.79106