Year Percent 2002-01-01 0.30 2003-01-01 0.30 2004-01-01 0.20 2005-01-01 0.20 2006-01-01 0.20 2007-01-01 0.15 2008-01-01 0.13 2009-01-01 0.18 2010-01-01 0.35 2011-01-01 0.33 2012-01-01 0.36 2013-01-01 0.57 2014-01-01 1.23 2015-01-01 1.19 2016-01-01 0.88