Year	Percent
1991-01-01	51.1980018615723
1992-01-01	50.9070014953613
1993-01-01	50.5610008239746
1994-01-01	49.5299987792969
1995-01-01	49.4500007629395
1996-01-01	49.5929985046387
1997-01-01	49.2470016479492
1998-01-01	48.1080017089844
1999-01-01	46.6370010375977
2000-01-01	45.0299987792969
2001-01-01	44.8590011596680
2002-01-01	44.4210014343262
2003-01-01	45.0449981689453
2004-01-01	46.1829986572266
2005-01-01	46.5820007324219
2006-01-01	46.8510017395020
2007-01-01	47.8429985046387
2008-01-01	48.7389984130859
2009-01-01	48.3660011291504
2010-01-01	46.5579986572266
2011-01-01	44.7859992980957
2012-01-01	43.2229995727539
2013-01-01	42.0970001220703
2014-01-01	43.3580017089844
2015-01-01	44.3330001831055
2016-01-01	44.7420005798340
2017-01-01	45.5519981384277