Year	Percent
1997-01-01	60.3048
1998-01-01	55.4902
1999-01-01	48.4723
2000-01-01	36.4336
2001-01-01	30.7055
2002-01-01	27.5668
2003-01-01	32.4112
2004-01-01	37.5469
2005-01-01	37.8404
2006-01-01	43.2944
2007-01-01	47.5097
2008-01-01	53.6893
2009-01-01	58.4199
2010-01-01	57.6875
2011-01-01	57.7983
2012-01-01	59.6795
2013-01-01	60.7665
2014-01-01	61.8313
2015-01-01	61.4848
2016-01-01	60.5913