Year	Percent
1989-01-01	18.3408
1990-01-01	18.8877
1991-01-01	18.3797
1992-01-01	26.1543
1993-01-01	49.5323
1994-01-01	77.4264
1995-01-01	80.2422
1996-01-01	95.4156
1997-01-01	63.6383
1998-01-01	40.3116
1999-01-01	47.8737
2000-01-01	39.1366
2001-01-01	28.8047
2002-01-01	24.3385
2003-01-01	24.3105
2004-01-01	27.8660
2005-01-01	33.3768
2006-01-01	45.3684
2007-01-01	59.4223
2008-01-01	47.2944
2009-01-01	39.9128
2010-01-01	62.0505
2011-01-01	74.0319
2012-01-01	79.9211
2013-01-01	81.8477
2014-01-01	82.8952
2015-01-01	84.3605
2016-01-01	76.5879
2017-01-01	82.1508