Year Percent 1991-01-01 41.1076000000000000 1992-01-01 22.2263000000000000 1993-01-01 6.5576399999999990 1994-01-01 2.8952200000000000 1995-01-01 1.5136700000000000 1996-01-01 2.2179300000000000 1997-01-01 3.9812500000000000 1998-01-01 4.3869000000000000 1999-01-01 3.4782400000000000 2000-01-01 3.4457199999999997 2001-01-01 2.5900700000000000 2002-01-01 2.3238100000000000 2003-01-01 2.9408300000000000 2004-01-01 1.6132799999999998 2005-01-01 1.0575700000000001 2006-01-01 0.8659270000000000 2007-01-01 0.8183390000000000 2008-01-01 0.3946190000000000 2009-01-01 0.3446470000000000 2010-01-01 0.9849620000000001 2011-01-01 2.8535200000000000 2012-01-01 4.2504599999999995 2013-01-01 9.9261600000000010 2014-01-01 10.2101000000000000 2015-01-01 12.2505000000000000 2016-01-01 15.2686000000000000