Year	Percent
1991-01-01	42.1040000915527
1992-01-01	41.0330009460449
1993-01-01	38.8240013122559
1994-01-01	38.0489997863770
1995-01-01	38.6479988098145
1996-01-01	39.1759986877441
1997-01-01	40.2849998474121
1998-01-01	41.6150016784668
1999-01-01	43.7050018310547
2000-01-01	45.5309982299805
2001-01-01	46.7260017395020
2002-01-01	47.7080001831055
2003-01-01	48.6489982604980
2004-01-01	49.5260009765625
2005-01-01	51.6209983825684
2006-01-01	52.7519989013672
2007-01-01	53.3209991455078
2008-01-01	52.2169990539551
2009-01-01	48.4939994812012
2010-01-01	47.5099983215332
2011-01-01	46.5830001831055
2012-01-01	44.5660018920898
2013-01-01	43.5390014648438
2014-01-01	44.2109985351563
2015-01-01	45.4710006713867
2016-01-01	46.6959991455078
2017-01-01	47.8510017395020