Year	Percent
1991-01-01	40.6450004577637
1992-01-01	43.6839981079102
1993-01-01	46.4949989318848
1994-01-01	48.7039985656738
1995-01-01	55.5519981384277
1996-01-01	49.6500015258789
1997-01-01	44.0810012817383
1998-01-01	46.2330017089844
1999-01-01	48.9459991455078
2000-01-01	51.3979988098145
2001-01-01	47.0629997253418
2002-01-01	47.5410003662109
2003-01-01	46.6809997558594
2004-01-01	35.1650009155273
2005-01-01	30.7129993438721
2006-01-01	23.8950004577637
2007-01-01	27.3339996337891
2008-01-01	23.9580001831055
2009-01-01	21.5179996490479
2010-01-01	21.8540000915527
2011-01-01	22.5359992980957
2012-01-01	27.5769996643066
2013-01-01	25.0569992065430
2014-01-01	25.7779998779297
2015-01-01	29.8980007171631
2016-01-01	24.2569999694824
2017-01-01	24.3010005950928