Year	Percent
1990-01-01	0.495
1991-01-01	0.570
1992-01-01	0.425
1993-01-01	0.485
1994-01-01	0.465
1995-01-01	0.400
1996-01-01	0.435
1997-01-01	0.440
1998-01-01	0.420
1999-01-01	0.460
2000-01-01	0.320
2001-01-01	0.460
2002-01-01	0.530
2003-01-01	0.425
2004-01-01	0.510
2005-01-01	0.560
2006-01-01	0.550
2007-01-01	0.520
2008-01-01	0.470
2009-01-01	0.470
2010-01-01	0.475
2011-01-01	0.470
2012-01-01	0.495
2013-01-01	0.515
2014-01-01	0.590
2015-01-01	0.890