Year Percent 1991-01-01 47.993600000000000 1992-01-01 45.747400000000000 1993-01-01 18.562200000000000 1994-01-01 7.744540000000000 1995-01-01 7.539389999999999 1996-01-01 8.503789999999999 1997-01-01 9.278720000000000 1998-01-01 9.725580000000000 1999-01-01 9.280180000000000 2000-01-01 10.771800000000000 2001-01-01 13.165400000000000 2002-01-01 15.839400000000000 2003-01-01 18.209300000000000 2004-01-01 21.375100000000000 2005-01-01 25.536300000000000 2006-01-01 28.725500000000000 2007-01-01 32.400200000000000 2008-01-01 36.192700000000000 2009-01-01 38.946800000000000 2010-01-01 35.766000000000000 2011-01-01 35.053500000000000 2012-01-01 37.588900000000000 2013-01-01 40.400800000000000 2014-01-01 41.732400000000000 2015-01-01 39.816900000000000 2016-01-01 37.211500000000000