Year	Percent
1991-01-01	36.4393
1992-01-01	21.8796
1993-01-01	25.5220
1994-01-01	29.9050
1995-01-01	29.7802
1996-01-01	33.0204
1997-01-01	35.7070
1998-01-01	39.3394
1999-01-01	40.7837
2000-01-01	43.6019
2001-01-01	48.7507
2002-01-01	52.7080
2003-01-01	52.8436
2004-01-01	52.8718
2005-01-01	48.1081
2006-01-01	48.0738
2007-01-01	50.7320
2008-01-01	55.4665
2009-01-01	59.7765
2010-01-01	61.2887
2011-01-01	62.2173
2012-01-01	64.6164
2013-01-01	64.1324
2014-01-01	63.8987
2015-01-01	65.6164
2016-01-01	66.9094