Year Percent 1999-01-01 1.2070400000000000 2000-01-01 1.4978200000000002 2001-01-01 4.0356000000000000 2002-01-01 12.5802000000000000 2003-01-01 14.2190000000000010 2004-01-01 15.2066000000000000 2005-01-01 16.2809000000000000 2006-01-01 17.3928000000000000 2007-01-01 15.7626000000000000 2008-01-01 15.0361000000000000 2009-01-01 19.5890000000000020 2010-01-01 18.6709000000000000 2011-01-01 17.2950000000000000 2012-01-01 20.3220000000000000 2013-01-01 19.8748000000000000 2014-01-01 22.6506000000000000 2015-01-01 21.4067000000000000 2016-01-01 21.1348000000000000