Year	Percent
1980-01-01	99.7637
1981-01-01	99.0936
1982-01-01	94.7317
1983-01-01	91.1023
1984-01-01	91.4414
1985-01-01	87.5609
1986-01-01	87.8546
1987-01-01	86.2248
1988-01-01	81.0838
1989-01-01	79.9205
1990-01-01	77.8200
1991-01-01	72.5197
1992-01-01	74.0617
1993-01-01	80.4506
1994-01-01	80.8345
1995-01-01	78.9347
1996-01-01	78.9311
1997-01-01	79.7674
1998-01-01	80.7118
1999-01-01	85.0155
2000-01-01	88.8487
2001-01-01	75.3529
2002-01-01	63.3640
2003-01-01	66.0177
2004-01-01	67.9614
2005-01-01	71.1031
2006-01-01	78.5183
2007-01-01	85.7200
2008-01-01	89.4101
2009-01-01	90.9915
2010-01-01	91.3282
2011-01-01	91.8709
2012-01-01	93.1742
2013-01-01	94.4856
2014-01-01	95.4750
2015-01-01	97.7296
2016-01-01	99.4306