Year Percent 1995 13.42277 1996 8.5536 1997 9.47929 1998 13.70163 2002 16.16084 2003 16.79084 2004 17.64536 2011 18.02201 2012 17.48323 2013 16.50328 2014 18.30194 2015 18.51579 2016 17.55718