Year Percent 1995-01-01 0.79 1996-01-01 0.96 1997-01-01 1.06 1998-01-01 1.07 1999-01-01 1.61 2000-01-01 1.56 2001-01-01 1.65 2002-01-01 1.51 2003-01-01 1.61 2004-01-01 1.70 2005-01-01 2.15 2006-01-01 2.21 2007-01-01 2.51 2008-01-01 1.45 2009-01-01 1.62 2010-01-01 3.03 2011-01-01 2.93 2012-01-01 3.24 2013-01-01 3.45 2014-01-01 3.87 2015-01-01 4.09 2016-01-01 4.57