Year Percent 1987 1.84098 1988 2.11099 1989 2.08491 1990 1.25636 1991 1.22855 1992 1.08347 1993 1.19865 1994 1.19256 1995 1.11576 1996 1.08559 1997 1.17017 1998 0.95129 1999 0.97414 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 0 2009 0 2010 0 2011 0 2012 0 2013 0 2014 0 2015 0 2016 0 2017 0