Year	Percent
1988-01-01	13.2184000000000000
1989-01-01	12.0793000000000000
1990-01-01	12.5852000000000000
1991-01-01	11.2567000000000000
1992-01-01	11.1078000000000000
1993-01-01	8.5882600000000000
1994-01-01	7.3364800000000000
1995-01-01	6.1302800000000000
1996-01-01	6.3142900000000000
1997-01-01	7.0478200000000000
1998-01-01	5.8159900000000000
1999-01-01	6.8126100000000000
2000-01-01	10.1399000000000000
2001-01-01	9.6138500000000000
2002-01-01	9.6797899999999990
2003-01-01	8.5013200000000000
2004-01-01	7.9581399999999990
2005-01-01	7.8450800000000000
2006-01-01	7.8217000000000000
2007-01-01	5.4415900000000000
2008-01-01	4.1307000000000000
2009-01-01	3.8011699999999995
2010-01-01	3.4414700000000000
2011-01-01	3.2919199999999997
2012-01-01	3.4710400000000003
2013-01-01	3.5866500000000000
2014-01-01	3.2117400000000003
2015-01-01	3.1500600000000000
2016-01-01	2.8788300000000000
2017-01-01	2.9673500000000000