Year Percent 1994-01-01 0.04 1995-01-01 0.26 1996-01-01 0.67 1997-01-01 1.21 1998-01-01 1.93 1999-01-01 2.97 2000-01-01 4.54 2001-01-01 5.86 2002-01-01 7.43 2003-01-01 8.62 2004-01-01 9.80 2005-01-01 12.48 2006-01-01 12.89 2007-01-01 13.50 2008-01-01 13.73 2009-01-01 17.71 2010-01-01 20.22 2011-01-01 17.65 2012-01-01 18.96 2013-01-01 18.64 2014-01-01 20.41 2015-01-01 20.87 2016-01-01 22.11