Year Percent 1990-01-01 0.11496200000000000 1991-01-01 0.13449900000000000 1992-01-01 0.14372400000000000 1993-01-01 0.12504100000000000 1994-01-01 0.09984600000000000 1995-01-01 0.10540400000000000 1996-01-01 0.12729700000000000 1997-01-01 0.15517800000000000 1998-01-01 0.13112100000000002 1999-01-01 0.16718300000000000 2000-01-01 0.19572699999999998 2001-01-01 0.19204900000000000 2002-01-01 0.19157900000000000 2003-01-01 0.22686199999999998 2004-01-01 0.21271900000000002 2005-01-01 0.19185200000000000 2006-01-01 0.18173100000000000 2007-01-01 0.15732500000000000 2008-01-01 0.16565200000000000 2009-01-01 0.18961400000000000 2010-01-01 0.18798299999999998 2011-01-01 0.19251500000000002 2012-01-01 0.17266300000000000 2013-01-01 0.18749600000000000 2014-01-01 0.16041300000000000 2015-01-01 0.16088600000000000 2016-01-01 0.19488200000000000