Year	Percent
1991-01-01	35.5699996948242
1992-01-01	32.2789993286133
1993-01-01	29.1250000000000
1994-01-01	31.0909996032715
1995-01-01	31.4780006408691
1996-01-01	32.4860000610352
1997-01-01	30.6340007781982
1998-01-01	32.3009986877441
1999-01-01	27.2150001525879
2000-01-01	31.7530002593994
2001-01-01	34.9599990844727
2002-01-01	33.9459991455078
2003-01-01	32.7599983215332
2004-01-01	30.2940006256104
2005-01-01	25.2800006866455
2006-01-01	22.6580009460449
2007-01-01	16.9300003051758
2008-01-01	14.5550003051758
2009-01-01	15.1770000457764
2010-01-01	14.9219999313354
2011-01-01	12.2430000305176
2012-01-01	10.3140001296997
2013-01-01	10.7819995880127
2014-01-01	12.5229997634888
2015-01-01	12.5559997558594
2016-01-01	11.5699996948242
2017-01-01	11.9790000915527