Year	Percent
1991-01-01	42.7290000915527
1992-01-01	41.9879989624023
1993-01-01	40.7379989624023
1994-01-01	38.4760017395020
1995-01-01	37.0540008544922
1996-01-01	37.0690002441406
1997-01-01	36.8790016174316
1998-01-01	36.6699981689453
1999-01-01	36.2280006408691
2000-01-01	36.5589981079102
2001-01-01	36.2470016479492
2002-01-01	35.4780006408691
2003-01-01	35.1040000915527
2004-01-01	34.3839988708496
2005-01-01	34.1780014038086
2006-01-01	33.5569992065430
2007-01-01	34.5200004577637
2008-01-01	37.1730003356934
2009-01-01	36.7410011291504
2010-01-01	35.0989990234375
2011-01-01	34.7290000915527
2012-01-01	34.2919998168945
2013-01-01	34.3260002136230
2014-01-01	34.0299987792969
2015-01-01	33.7989997863770
2016-01-01	35.0169982910156
2017-01-01	34.6850013732910