Year	Percent
1980-01-01	4.9211900000000000
1981-01-01	5.3506500000000000
1982-01-01	6.5515300000000005
1983-01-01	6.6474600000000010
1984-01-01	6.8588300000000000
1985-01-01	7.3974400000000000
1986-01-01	9.2321400000000000
1987-01-01	8.6515700000000000
1988-01-01	7.4902700000000000
1989-01-01	6.5124300000000000
1990-01-01	6.8561900000000000
1991-01-01	8.1167699999999990
1992-01-01	9.3261200000000000
1993-01-01	12.2165000000000000
1994-01-01	14.7373000000000000
1995-01-01	15.6049000000000000
1996-01-01	14.9333000000000000
1997-01-01	14.0291000000000000
1998-01-01	15.9381000000000000
1999-01-01	14.4379999999999990
2000-01-01	11.5379000000000000
2001-01-01	11.3623000000000000
2002-01-01	11.2781000000000000
2003-01-01	9.8859800000000000
2004-01-01	8.5934900000000000
2005-01-01	7.4377699999999995
2006-01-01	6.5795500000000000
2007-01-01	5.8371500000000000
2008-01-01	5.1248600000000000
2009-01-01	7.1873300000000000
2010-01-01	7.1372700000000000
2011-01-01	6.8264400000000000
2012-01-01	7.1272500000000000
2013-01-01	6.8625500000000000
2014-01-01	6.9903699999999995
2015-01-01	7.5221500000000000
2016-01-01	7.5320000000000000