Year	Percent
1988-01-01	18.4926
1989-01-01	24.0234
1990-01-01	23.7054
1991-01-01	72.4441
1992-01-01	79.0977
1993-01-01	72.8817
1994-01-01	70.2089
1995-01-01	76.0877
1996-01-01	82.3664
1997-01-01	90.1777
1998-01-01	95.4125
1999-01-01	98.4702
2000-01-01	99.5685
2001-01-01	99.9432
2002-01-01	99.9374
2003-01-01	99.9494
2004-01-01	92.5043
2005-01-01	91.0599
2006-01-01	91.6561
2007-01-01	91.1199
2008-01-01	91.7457
2009-01-01	93.9044
2010-01-01	95.2103
2011-01-01	95.8163
2012-01-01	96.2076
2013-01-01	96.5769
2014-01-01	96.2796
2015-01-01	96.6655
2016-01-01	92.8141