Year	Percent
1973-01-01	6.4902700000000000
1974-01-01	6.5263000000000000
1975-01-01	7.1468700000000000
1976-01-01	8.4258500000000000
1977-01-01	9.7526600000000000
1978-01-01	11.1685000000000000
1979-01-01	15.6957000000000000
1980-01-01	13.0051000000000000
1981-01-01	12.1775000000000000
1982-01-01	11.6544000000000000
1983-01-01	11.2489000000000000
1984-01-01	11.1195000000000000
1985-01-01	10.4467000000000000
1986-01-01	9.7470699999999990
1987-01-01	8.4928300000000000
1988-01-01	6.4570900000000000
1989-01-01	6.3129300000000010
1990-01-01	7.3516699999999995
1991-01-01	6.8967700000000000
1992-01-01	8.4352800000000000
1993-01-01	7.2055200000000000
1994-01-01	7.4865100000000010
1995-01-01	5.3402900000000000
1996-01-01	4.9371300000000010
1997-01-01	4.5406200000000000
1998-01-01	4.2330100000000000
1999-01-01	4.3388900000000000
2000-01-01	4.4010500000000000
2001-01-01	4.4482400000000000
2002-01-01	4.5670400000000000
2003-01-01	5.6758800000000000
2004-01-01	6.0211300000000000
2005-01-01	6.3189900000000000
2006-01-01	6.5301100000000000
2007-01-01	7.9033500000000000
2008-01-01	10.5244000000000000
2009-01-01	13.0826000000000000
2010-01-01	14.5955000000000000
2011-01-01	16.4618000000000000
2012-01-01	16.9626000000000000
2013-01-01	14.9475000000000000
2014-01-01	14.0554000000000000
2015-01-01	13.8323000000000000
2016-01-01	13.4178000000000000