Year Percent 1992-01-01 0.62988000000000000 1993-01-01 0.64725200000000000 1994-01-01 0.65969300000000000 1995-01-01 0.60127700000000010 1996-01-01 0.54292700000000000 1997-01-01 0.57801700000000000 1998-01-01 0.64855800000000000 1999-01-01 0.53468600000000000 2000-01-01 0.46197100000000000 2001-01-01 0.55936400000000010 2002-01-01 0.61291500000000000 2003-01-01 0.56347100000000000 2004-01-01 0.52660600000000000 2005-01-01 0.44273000000000000 2006-01-01 0.39977399999999996 2007-01-01 0.38356799999999996 2008-01-01 0.34019000000000000 2009-01-01 0.40591300000000000 2010-01-01 0.34648000000000000 2011-01-01 0.28243600000000000 2012-01-01 0.26919499999999996 2013-01-01 0.26080200000000000 2014-01-01 0.28581599999999996 2015-01-01 0.38572700000000000