Year	Percent
1991-01-01	49.2890014648438
1992-01-01	49.5579986572266
1993-01-01	49.8619995117188
1994-01-01	50.1739997863770
1995-01-01	50.4580001831055
1996-01-01	50.9799995422363
1997-01-01	51.4850006103516
1998-01-01	51.9939994812012
1999-01-01	52.5550003051758
2000-01-01	53.2249984741211
2001-01-01	54.6310005187988
2002-01-01	56.2540016174316
2003-01-01	58.1170005798340
2004-01-01	59.7869987487793
2005-01-01	61.4109992980957
2006-01-01	63.4259986877441
2007-01-01	63.0519981384277
2008-01-01	62.9970016479492
2009-01-01	62.6459999084473
2010-01-01	63.0429992675781
2011-01-01	63.1489982604980
2012-01-01	63.0960006713867
2013-01-01	63.4550018310547
2014-01-01	63.5400009155273
2015-01-01	62.8440017700195
2016-01-01	62.0289993286133
2017-01-01	62.5460014343262