Year	Percent
1991-01-01	45.5660018920898
1992-01-01	45.3590011596680
1993-01-01	44.6759986877441
1994-01-01	44.6080017089844
1995-01-01	46.1730003356934
1996-01-01	46.5439987182617
1997-01-01	45.7540016174316
1998-01-01	45.6930007934570
1999-01-01	43.8110008239746
2000-01-01	41.7890014648438
2001-01-01	41.3590011596680
2002-01-01	41.8989982604980
2003-01-01	43.3740005493164
2004-01-01	44.9259986877441
2005-01-01	45.2999992370605
2006-01-01	47.6430015563965
2007-01-01	50.0929985046387
2008-01-01	52.0369987487793
2009-01-01	50.6250000000000
2010-01-01	47.9179992675781
2011-01-01	46.6180000305176
2012-01-01	46.5600013732910
2013-01-01	46.8919982910156
2014-01-01	47.9669990539551
2015-01-01	49.2280006408691
2016-01-01	49.4070014953613
2017-01-01	50.1500015258789