Year	Percent
1991-01-01	27.1800003051758
1992-01-01	27.4580001831055
1993-01-01	26.8400001525879
1994-01-01	25.8080005645752
1995-01-01	25.0249996185303
1996-01-01	24.2719993591309
1997-01-01	23.8099994659424
1998-01-01	23.2439994812012
1999-01-01	23.1840000152588
2000-01-01	24.3430004119873
2001-01-01	24.9319992065430
2002-01-01	27.4599990844727
2003-01-01	26.0939998626709
2004-01-01	27.6800003051758
2005-01-01	29.2150001525879
2006-01-01	33.8199996948242
2007-01-01	29.5990009307861
2008-01-01	28.8220005035400
2009-01-01	29.4570007324219
2010-01-01	29.0030002593994
2011-01-01	28.7709999084473
2012-01-01	27.8369998931885
2013-01-01	28.9650001525879
2014-01-01	30.1229991912842
2015-01-01	28.9759998321533
2016-01-01	24.8719997406006
2017-01-01	25.0209999084473