Year Percent 1996-01-01 31.947337721856600 1997-01-01 23.435427849700500 1998-01-01 10.457382584672100 1999-01-01 37.030925836934400 2000-01-01 18.700734283802300 2001-01-01 6.919679894230410 2002-01-01 2.134209863102430 2003-01-01 2.974612951843540 2004-01-01 4.110650847233830 2005-01-01 4.338673918443100 2006-01-01 5.552123331625400 2007-01-01 10.230103266048500 2008-01-01 24.520102423410100 2009-01-01 6.836562481053630 2010-01-01 7.967722255796910 2011-01-01 16.636326273149600 2012-01-01 2.768442365409480 2013-01-01 6.613752023580860 2014-01-01 7.534247297758820 2015-01-01 6.503318389933810 2016-01-01 0.388838296895887 2017-01-01 3.175309863799400