Year Percent 2006-01-01 2.738421316020940 2007-01-01 6.794773539301560 2008-01-01 12.041458350510900 2009-01-01 4.530176591327980 2010-01-01 6.149885367501780 2011-01-01 11.273414605593700 2012-01-01 10.884695658563000 2013-01-01 3.805630009194380 2014-01-01 2.120001757181390 2015-01-01 0.953206658777419 2016-01-01 0.502509413611771 2017-01-01 2.716703078770830