Year Percent 1993-01-01 65.71600000000001 1994-01-01 66.26280000000000 1995-01-01 68.62920000000000 1996-01-01 67.48530000000000 1997-01-01 65.95230000000000 1998-01-01 61.32280000000000 1999-01-01 54.59290000000000 2000-01-01 49.60930000000000 2001-01-01 46.10370000000000 2002-01-01 44.50060000000000 2003-01-01 44.64680000000000 2004-01-01 44.25160000000000 2005-01-01 44.07420000000000 2006-01-01 47.16580000000000 2007-01-01 51.14020000000000 2008-01-01 58.13510000000000 2009-01-01 61.46770000000000 2010-01-01 61.48860000000000 2011-01-01 64.10380000000000 2012-01-01 68.63740000000000 2013-01-01 70.13810000000000 2014-01-01 67.93560000000000 2015-01-01 65.38180000000000 2016-01-01 63.66790000000000