Year Percent 1990-01-01 0.07962700000000000 1991-01-01 0.18407700000000000 1992-01-01 0.19136199999999998 1993-01-01 0.19195000000000000 1994-01-01 0.19976400000000000 1995-01-01 0.20311099999999999 1996-01-01 0.20079900000000000 1997-01-01 0.20272400000000000 1998-01-01 0.18984700000000002 1999-01-01 0.17552100000000000 2000-01-01 0.18016400000000002 2001-01-01 0.16331800000000002 2002-01-01 0.19586900000000002 2003-01-01 0.19556800000000002 2004-01-01 0.21020600000000000 2005-01-01 0.21326399999999998 2006-01-01 0.18700400000000000 2007-01-01 0.19430999999999998 2008-01-01 0.20014900000000000 2009-01-01 0.19710800000000000 2010-01-01 0.20743600000000000 2011-01-01 0.21017900000000000 2012-01-01 0.20351800000000000 2013-01-01 0.19148800000000002 2014-01-01 0.18189000000000000 2015-01-01 0.17207100000000000