Year Percent 1990-01-01 20.1180 1991-01-01 21.5884 1992-01-01 27.6145 1993-01-01 32.7721 1994-01-01 33.6841 1995-01-01 38.6397 1996-01-01 40.3612 1997-01-01 41.6763 1998-01-01 42.9232 1999-01-01 42.5402 2000-01-01 37.6491 2001-01-01 37.7046 2002-01-01 33.7710 2003-01-01 35.2328 2004-01-01 35.0192 2005-01-01 35.9344 2006-01-01 36.8610 2007-01-01 38.7365 2008-01-01 39.0649 2009-01-01 51.4302 2010-01-01 60.6745 2011-01-01 61.1400 2012-01-01 55.9724 2013-01-01 53.5070 2014-01-01 52.4602 2015-01-01 50.0264 2016-01-01 47.0513