Year	Percent
1973-01-01	11.1564000000000000
1974-01-01	12.1474000000000000
1975-01-01	9.7356500000000000
1976-01-01	9.0844000000000000
1977-01-01	6.1687400000000010
1978-01-01	5.5131800000000000
1979-01-01	3.9513300000000005
1980-01-01	4.0193100000000000
1981-01-01	5.1479200000000000
1982-01-01	5.1468099999999990
1983-01-01	4.3704100000000000
1984-01-01	2.6406000000000000
1985-01-01	2.6945600000000000
1986-01-01	3.5686300000000000
1987-01-01	2.9969000000000000
1988-01-01	2.1635000000000000
1989-01-01	2.2278200000000000
1990-01-01	3.4988000000000000
1991-01-01	3.4857699999999996
1992-01-01	4.2675700000000000
1993-01-01	4.2846600000000000
1994-01-01	5.2374900000000000
1995-01-01	5.5334300000000000
1996-01-01	6.3854600000000000
1997-01-01	7.2620600000000010
1998-01-01	7.7741899999999990
1999-01-01	8.7346899999999990
2000-01-01	9.3903600000000010
2001-01-01	10.9290000000000000
2002-01-01	12.5497000000000000
2003-01-01	13.9103000000000000
2004-01-01	13.2561000000000000
2005-01-01	13.1745000000000000
2006-01-01	13.1494000000000000
2007-01-01	13.6155000000000000
2008-01-01	14.3121000000000000
2009-01-01	14.4763000000000000
2010-01-01	15.5095000000000000
2011-01-01	16.5222000000000000
2012-01-01	16.8706000000000000
2013-01-01	17.7462000000000000
2014-01-01	18.3804000000000000
2015-01-01	18.3017000000000000
2016-01-01	18.6909000000000000