Year Percent 1990 3.77 1994 5.64 1998 2.48 2003 3.75 2004 2.27 2008 2.36 2012 3.85 2013 4.05 2014 2.51 2015 2.98 2016 3.64 2017 3.65 2018 2.6 2019 1.91