Year	Percent
1997-01-01	60.2350
1998-01-01	55.4109
1999-01-01	48.3682
2000-01-01	36.3482
2001-01-01	30.5383
2002-01-01	27.2282
2003-01-01	32.0448
2004-01-01	37.2578
2005-01-01	37.5713
2006-01-01	42.3794
2007-01-01	45.9501
2008-01-01	51.8659
2009-01-01	56.1348
2010-01-01	54.8666
2011-01-01	53.8215
2012-01-01	54.1480
2013-01-01	54.2972
2014-01-01	54.2699
2015-01-01	52.9807
2016-01-01	52.0622