Year	Percent
1979-01-01	11.7024395166667
1980-01-01	11.3312291250000
1981-01-01	10.1550972416667
1982-01-01	13.2610206166667
1983-01-01	19.3785964750000
1984-01-01	17.4902109250000
1985-01-01	15.5372069416667
1986-01-01	15.2437235333333
1987-01-01	15.0170021750000
1988-01-01	13.3456747250000
1989-01-01	10.6373124333333
1990-01-01	13.2147912583333
1991-01-01	18.5411514666667
1992-01-01	20.7485501166667
1993-01-01	19.6846898250000
1994-01-01	17.3990144333333
1995-01-01	15.5189553416667
1996-01-01	16.3840080833333
1997-01-01	16.9026293166667
1998-01-01	15.2984622500000
1999-01-01	13.7275323000000
2000-01-01	12.8774874000000
2001-01-01	14.5887267000000
2002-01-01	13.7716218666667
2003-01-01	12.5943133666667
2004-01-01	11.8372818833333
2005-01-01	10.8723174500000
2006-01-01	10.5392376166667
2007-01-01	9.4656967500000
2008-01-01	9.0011394750000
2009-01-01	12.4759767666667
2010-01-01	11.9297398500000
2011-01-01	11.9225298666667
2012-01-01	12.4439269166667
2013-01-01	13.0227960083333
2014-01-01	14.1031831833333
2015-01-01	14.2192544583333
2016-01-01	13.8047351083333
2017-01-01	13.6553975333333