Year	Percent
1991-01-01	38.6650009155273
1992-01-01	41.0110015869141
1993-01-01	41.9259986877441
1994-01-01	43.5690002441406
1995-01-01	45.8429985046387
1996-01-01	44.9910011291504
1997-01-01	45.4140014648438
1998-01-01	45.5279998779297
1999-01-01	44.0779991149902
2000-01-01	44.6640014648438
2001-01-01	45.7690010070801
2002-01-01	45.9780006408691
2003-01-01	46.6769981384277
2004-01-01	47.0390014648438
2005-01-01	47.0489997863770
2006-01-01	47.4729995727539
2007-01-01	47.7420005798340
2008-01-01	47.9710006713867
2009-01-01	48.1699981689453
2010-01-01	49.1180000305176
2011-01-01	49.5950012207031
2012-01-01	50.0359992980957
2013-01-01	50.8979988098145
2014-01-01	49.8409996032715
2015-01-01	49.7210006713867
2016-01-01	49.0279998779297
2017-01-01	49.0769996643066