Year Percent 1991 -0.39153 1995 0.04267 1996 0.02767 1997 0.02995 1998 0 1999 -0.02407 2000 0 2005 0 2006 0 2007 0 2008 0 2009 0 2010 0 2011 0 2012 0 2013 0 2014 0 2015 0