Year Percent 1990-01-01 6.7956199999999995 1991-01-01 6.2824300000000010 1992-01-01 5.8778000000000000 1993-01-01 5.4599199999999990 1994-01-01 4.7507000000000000 1995-01-01 4.8985300000000000 1996-01-01 4.2991000000000000 1997-01-01 7.9624300000000000 1998-01-01 8.9251899999999990 1999-01-01 8.2378900000000000 2000-01-01 8.9448200000000000 2001-01-01 8.5271200000000000 2002-01-01 8.6831900000000000 2003-01-01 9.9258500000000000 2004-01-01 11.5042000000000000 2005-01-01 11.5724000000000000 2006-01-01 11.5389000000000000 2007-01-01 12.6816000000000000 2008-01-01 13.0487000000000000 2009-01-01 15.7409000000000000 2010-01-01 14.4050000000000000 2011-01-01 14.7325000000000000 2012-01-01 14.2592000000000000 2013-01-01 17.3314000000000000