Year	Percent
1981-01-01	14.11293893129770
1982-01-01	11.19240458015270
1983-01-01	11.96645038167940
1984-01-01	12.71221374045800
1985-01-01	9.38828244274809
1986-01-01	6.42011450381679
1987-01-01	6.67019083969466
1988-01-01	6.87412213740458
1989-01-01	5.98992366412214
1990-01-01	7.64965648854962
1991-01-01	8.62867557251908
1992-01-01	10.11320610687020
1993-01-01	9.49545801526718
1994-01-01	9.04636259541985
1995-01-01	8.29777099236641
1996-01-01	9.69849618320611
1997-01-01	10.12050000000000
1998-01-01	13.57988931297710
1999-01-01	13.49816793893130
2000-01-01	12.74793893129770
2001-01-01	11.17487277353690
2002-01-01	11.72885380518150
2003-01-01	12.41303313355710
2004-01-01	11.55046919616010
2005-01-01	9.88973374901603
2006-01-01	10.02963364961240
2007-01-01	9.34877388110172
2008-01-01	7.92860655351996
2009-01-01	8.10884550738486
2010-01-01	6.75715858894194
2011-01-01	5.97836722535758
2012-01-01	5.52026784158456
2013-01-01	5.40049448912265
2014-01-01	4.85151432272462