Year	Percent
1983-01-01	22.450
1984-01-01	24.220
1985-01-01	29.220
1986-01-01	25.020
1987-01-01	23.710
1988-01-01	22.880
1989-01-01	23.500
1990-01-01	22.845
1991-01-01	26.575
1992-01-01	27.850
1993-01-01	12.120
1994-01-01	4.710
1995-01-01	6.970
1996-01-01	12.680
1997-01-01	3.090
1998-01-01	5.000
1999-01-01	38.510
2000-01-01	51.480
2001-01-01	49.750
2002-01-01	55.060
2003-01-01	51.960
2004-01-01	67.500
2005-01-01	76.930
2006-01-01	90.280
2007-01-01	101.010
2008-01-01	93.490
2009-01-01	90.760
2010-01-01	89.650
2011-01-01	74.050
2012-01-01	79.250
2013-01-01	73.200
2014-01-01	64.440
2015-01-01	79.615