Year Percent 1989-01-01 4.0767500000000000 1990-01-01 3.6407900000000000 1991-01-01 3.4032199999999997 1992-01-01 3.7922800000000003 1993-01-01 5.5949599999999995 1994-01-01 6.7165300000000006 1995-01-01 6.6805900000000000 1996-01-01 6.5078700000000000 1997-01-01 7.7235400000000000 1998-01-01 15.0940000000000010 1999-01-01 14.0038000000000000 2000-01-01 13.7459999999999990 2001-01-01 14.7115000000000000 2002-01-01 15.5401000000000000 2003-01-01 16.8070000000000020 2004-01-01 17.1147000000000000 2005-01-01 16.6657000000000000 2006-01-01 16.0229000000000000 2007-01-01 18.4556000000000000 2008-01-01 21.2774000000000000 2009-01-01 24.5171000000000000 2010-01-01 29.7899000000000000