Year Percent 1996 5.35 1997 5.67 1998 5.36 2006 4.57 2007 4.8 2009 5.53 2010 3.86 2011 3.55 2012 2.86 2013 2.7 2014 3.05 2015 3.1 2016 3.44 2017 3.37 2018 3.16 2019 3.25 2020 0.03