Year Percent 1998-01-01 23.7632000000000000 1999-01-01 11.2114000000000000 2000-01-01 21.0000000000000000 2001-01-01 16.7000000000000000 2002-01-01 11.8988000000000000 2003-01-01 10.5967000000000000 2004-01-01 14.9959999999999990 2005-01-01 19.2123000000000000 2006-01-01 16.3897000000000000 2007-01-01 16.7898000000000000 2008-01-01 17.2490000000000020 2009-01-01 12.9900000000000000 2010-01-01 14.9803000000000000 2011-01-01 11.0078000000000000 2012-01-01 7.3489800000000000 2013-01-01 7.1810199999999990 2014-01-01 5.1560000000000010 2015-01-01 6.4311300000000005 2016-01-01 4.6091600000000000