Year Percent 1996 0 1997 0 1998 0 1999 3.57 2000 4 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 0 2013 1.61 2014 1.43 2015 1.28 2016 1.19 2017 0 2018 0 2019 0.93 2020 1.6