Year Percent 1961 3.223 1962 -0.07571 1963 1.78919 1964 3.28721 1965 2.98297 1966 2.68442 1967 4.865 1968 2.25206 1969 4.75402 1970 5.13321 1971 5.18534 1972 6.18904 1973 8.98327 1974 16.38147 1975 16.48963 1976 14.01838 1977 11.41853 1978 8.23603 1979 8.63489 1980 10.0157 1981 9.52596 1982 11.70903 1983 10.15768 1984 7.86335 1985 4.62854 1986 6.42849 1987 7.12719 1988 7.29937 1989 9.24796 1990 6.10436 1991 3.0247 1992 1.45667 1993 0.87971 1994 1.02698 1995 2.27265 1996 2.69578 1997 1.23334 1998 1.2729 1999 0.35507 2000 2.57948 2001 4.62148 2002 2.86026 2003 3.11341 2004 3.30903 2005 3.79576 2006 5.09293 2007 5.01431 2008 4.52509 2009 5.00347 2010 1.1638 2011 6.25869 2012 1.87444 2013 -0.1579 2014 1.43995 2015 -0.72803 2016 -0.45837 2017 3.70145