Year Percent 1989-01-01 22.4792 1990-01-01 23.0213 1991-01-01 22.8893 1992-01-01 22.7387 1993-01-01 22.4445 1994-01-01 24.7179 1995-01-01 25.8768 1996-01-01 25.6973 1997-01-01 28.2304 1998-01-01 29.5901 1999-01-01 30.6903 2000-01-01 33.0900 2001-01-01 34.9551 2002-01-01 34.5715 2003-01-01 35.4119 2004-01-01 37.6769 2005-01-01 39.5760 2006-01-01 41.3406 2007-01-01 42.6155 2008-01-01 44.9822 2009-01-01 42.6255 2010-01-01 40.9003 2011-01-01 40.2258 2012-01-01 41.4671 2013-01-01 44.1833 2014-01-01 45.8547 2015-01-01 48.8584 2016-01-01 53.0218