Year	Percent
1980-01-01	17.553500000000000
1981-01-01	20.495900000000000
1982-01-01	21.468500000000000
1983-01-01	24.819500000000000
1984-01-01	25.738700000000000
1985-01-01	28.768600000000000
1986-01-01	29.336300000000000
1987-01-01	35.954300000000000
1988-01-01	38.575500000000000
1989-01-01	41.367400000000000
1990-01-01	40.088900000000000
1991-01-01	34.762100000000000
1992-01-01	36.998200000000000
1993-01-01	41.809600000000000
1994-01-01	39.194500000000000
1995-01-01	34.240500000000000
1996-01-01	33.052700000000000
1997-01-01	31.171300000000000
1998-01-01	28.143300000000000
1999-01-01	28.956600000000000
2000-01-01	31.237900000000000
2001-01-01	30.139800000000000
2002-01-01	27.674500000000000
2003-01-01	20.657900000000000
2004-01-01	17.791500000000000
2005-01-01	21.561200000000000
2006-01-01	18.663700000000000
2007-01-01	15.665200000000000
2008-01-01	15.139000000000001
2009-01-01	17.615200000000000
2010-01-01	27.893500000000000
2011-01-01	28.566500000000000
2012-01-01	14.769100000000000
2013-01-01	12.075600000000000
2014-01-01	13.189000000000000
2015-01-01	13.452300000000000
2016-01-01	10.937500000000000