Year	Percent
1991-01-01	62.7890014648438
1992-01-01	62.9939994812012
1993-01-01	60.9070014953613
1994-01-01	57.7529983520508
1995-01-01	56.2389984130859
1996-01-01	55.1559982299805
1997-01-01	52.6889991760254
1998-01-01	50.9760017395020
1999-01-01	53.5839996337891
2000-01-01	55.3919982910156
2001-01-01	55.2120018005371
2002-01-01	56.3590011596680
2003-01-01	55.8349990844727
2004-01-01	56.4490013122559
2005-01-01	57.1469993591309
2006-01-01	57.3590011596680
2007-01-01	58.7589988708496
2008-01-01	59.0029983520508
2009-01-01	57.7449989318848
2010-01-01	58.3580017089844
2011-01-01	59.2529983520508
2012-01-01	59.9879989624023
2013-01-01	59.9720001220703
2014-01-01	60.2410011291504
2015-01-01	60.1119995117188
2016-01-01	60.2960014343262
2017-01-01	60.2280006408691