Year Percent 1990-01-01 76.69800000000001 1991-01-01 79.55740000000000 1992-01-01 75.56670000000000 1993-01-01 76.70020000000000 1994-01-01 90.34680000000000 1995-01-01 98.10310000000000 1996-01-01 98.67620000000000 1997-01-01 94.81950000000000 1998-01-01 94.00420000000000 1999-01-01 91.39590000000000 2000-01-01 84.82020000000000 2001-01-01 83.92230000000000 2002-01-01 86.01310000000000 2003-01-01 89.02580000000000 2004-01-01 86.06070000000000 2005-01-01 79.15730000000000 2006-01-01 77.12730000000000 2007-01-01 81.10670000000000 2008-01-01 80.17630000000000 2009-01-01 86.77410000000000 2010-01-01 93.22030000000000 2011-01-01 91.15990000000000