Year	Percent
1991-01-01	59.6180000305176
1992-01-01	55.0660018920898
1993-01-01	51.4749984741211
1994-01-01	50.6640014648438
1995-01-01	49.6619987487793
1996-01-01	49.9599990844727
1997-01-01	51.0000000000000
1998-01-01	52.1430015563965
1999-01-01	53.7039985656738
2000-01-01	54.2360000610352
2001-01-01	54.9199981689453
2002-01-01	54.9230003356934
2003-01-01	54.6419982910156
2004-01-01	54.2809982299805
2005-01-01	55.5209999084473
2006-01-01	56.3139991760254
2007-01-01	57.1049995422363
2008-01-01	57.5970001220703
2009-01-01	55.4539985656738
2010-01-01	54.8199996948242
2011-01-01	55.1660003662109
2012-01-01	55.0719985961914
2013-01-01	54.2120018005371
2014-01-01	53.7719993591309
2015-01-01	53.3079986572266
2016-01-01	53.3149986267090
2017-01-01	53.2350006103516