Year Percent 1999-01-01 0.07 2000-01-01 0.04 2001-01-01 0.03 2002-01-01 0.04 2003-01-01 0.05 2004-01-01 0.14 2005-01-01 0.20 2006-01-01 0.59 2007-01-01 1.44 2008-01-01 0.45 2009-01-01 0.52 2010-01-01 0.64 2011-01-01 0.71 2012-01-01 0.64 2013-01-01 0.94 2014-01-01 1.03 2015-01-01 0.98 2016-01-01 1.23