Year Percent 1997-01-01 0.0004300000000000000 1998-01-01 0.0007360000000000000 1999-01-01 0.0008759999999999999 2000-01-01 0.0016489999999999999 2001-01-01 0.0300070000000000000 2002-01-01 0.0456899999999999950 2003-01-01 0.0124650000000000000 2004-01-01 0.0150540000000000000 2005-01-01 0.0290490000000000020 2006-01-01 0.0341389999999999960 2007-01-01 0.0404630000000000000 2008-01-01 0.0454139999999999960 2009-01-01 0.0610250000000000000 2010-01-01 0.0661530000000000000 2011-01-01 0.0792030000000000000 2012-01-01 0.0646120000000000000 2013-01-01 0.0721340000000000000 2014-01-01 0.0744789999999999900 2015-01-01 0.0694450000000000000 2016-01-01 0.0617360000000000000