Year	Percent
1991-01-01	23.4099998474121
1992-01-01	23.8059997558594
1993-01-01	25.7999992370605
1994-01-01	26.6170005798340
1995-01-01	26.7010002136230
1996-01-01	29.7840003967285
1997-01-01	29.8090000152588
1998-01-01	28.8509998321533
1999-01-01	30.8209991455078
2000-01-01	28.7660007476807
2001-01-01	27.6930007934570
2002-01-01	25.5970001220703
2003-01-01	25.2630004882813
2004-01-01	25.9599990844727
2005-01-01	25.6499996185303
2006-01-01	24.7840003967285
2007-01-01	22.5310001373291
2008-01-01	21.7329998016357
2009-01-01	25.5820007324219
2010-01-01	32.8440017700195
2011-01-01	44.5569992065430
2012-01-01	55.2519989013672
2013-01-01	58.2109985351563
2014-01-01	52.4399986267090
2015-01-01	49.8170013427734
2016-01-01	47.2779998779297
2017-01-01	43.5970001220703