Year Percent 1999-01-01 11.6542 2000-01-01 15.8526 2001-01-01 14.4683 2002-01-01 11.5719 2003-01-01 14.3321 2004-01-01 17.6863 2005-01-01 18.5644 2006-01-01 22.2303 2007-01-01 26.0552 2008-01-01 12.9291 2009-01-01 20.8668 2010-01-01 28.8121 2011-01-01 22.8473 2012-01-01 32.7984 2013-01-01 42.6779 2014-01-01 46.8894 2015-01-01 67.2270 2016-01-01 56.6732