Year Percent 1991-01-01 35.063300000000000 1992-01-01 19.697500000000000 1993-01-01 19.449600000000000 1994-01-01 20.315800000000000 1995-01-01 20.910700000000000 1996-01-01 23.794500000000000 1997-01-01 24.148500000000000 1998-01-01 26.467000000000000 1999-01-01 29.504000000000000 2000-01-01 32.580800000000000 2001-01-01 34.571300000000000 2002-01-01 36.048600000000000 2003-01-01 38.021000000000000 2004-01-01 42.497600000000000 2005-01-01 47.244200000000000 2006-01-01 54.127400000000000 2007-01-01 61.943000000000005 2008-01-01 72.000900000000000 2009-01-01 82.004500000000000 2010-01-01 84.507700000000000 2011-01-01 83.237500000000000 2012-01-01 82.316800000000000 2013-01-01 72.976900000000000 2014-01-01 59.162900000000000 2015-01-01 51.365900000000000 2016-01-01 47.281600000000000