Year Percent 1999 8.90157 2000 10.09353 2001 13.45257 2002 11.70529 2003 10.99731 2008 14.08204 2009 16.25969 2010 11.03829 2011 11.42989 2012 11.65632 2013 11.50048 2014 13.57499 2015 13.01014