Year	Percent
1990-01-01	2.090
1991-01-01	2.135
1992-01-01	2.165
1993-01-01	2.185
1994-01-01	2.050
1995-01-01	1.990
1996-01-01	2.085
1997-01-01	2.055
1998-01-01	1.895
1999-01-01	1.840
2000-01-01	1.920
2001-01-01	1.880
2002-01-01	2.120
2003-01-01	2.180
2004-01-01	2.180
2005-01-01	2.140
2006-01-01	2.020
2007-01-01	1.930
2008-01-01	1.750
2009-01-01	1.840
2010-01-01	1.840
2011-01-01	1.720
2012-01-01	1.740
2013-01-01	1.840
2014-01-01	1.680
2015-01-01	1.700