Year	Percent
1991-01-01	55.7060012817383
1992-01-01	53.8639984130859
1993-01-01	54.8569984436035
1994-01-01	65.7979965209961
1995-01-01	60.1230010986328
1996-01-01	66.9489974975586
1997-01-01	57.8110008239746
1998-01-01	59.8089981079102
1999-01-01	57.8559989929199
2000-01-01	64.8300018310547
2001-01-01	58.3979988098145
2002-01-01	58.8260002136230
2003-01-01	59.1440010070801
2004-01-01	60.1889991760254
2005-01-01	60.0499992370605
2006-01-01	49.6080017089844
2007-01-01	39.0800018310547
2008-01-01	34.7919998168945
2009-01-01	38.6520004272461
2010-01-01	42.0999984741211
2011-01-01	35.9770011901855
2012-01-01	40.5470008850098
2013-01-01	41.4630012512207
2014-01-01	35.3740005493164
2015-01-01	37.6430015563965
2016-01-01	37.6189994812012
2017-01-01	31.8159999847412