Year	Percent
1999-01-01	0.460
2000-01-01	0.470
2001-01-01	0.500
2002-01-01	0.560
2003-01-01	0.885
2004-01-01	1.000
2005-01-01	1.335
2006-01-01	2.290
2007-01-01	2.830
2008-01-01	1.440
2009-01-01	2.030
2010-01-01	2.625
2011-01-01	2.700
2012-01-01	2.790
2013-01-01	2.975
2014-01-01	3.495
2015-01-01	4.360
