Year	Percent
1989-01-01	9.360
1990-01-01	9.570
1991-01-01	9.510
1992-01-01	9.400
1993-01-01	8.880
1994-01-01	9.310
1995-01-01	9.250
1996-01-01	9.120
1997-01-01	9.640
1998-01-01	9.700
1999-01-01	7.625
2000-01-01	8.790
2001-01-01	9.140
2002-01-01	9.545
2003-01-01	8.940
2004-01-01	9.105
2005-01-01	11.485
2006-01-01	11.040
2007-01-01	10.550
2008-01-01	10.470
2009-01-01	11.580
2010-01-01	8.470
2011-01-01	8.375
2012-01-01	7.975
2013-01-01	7.950
2014-01-01	9.140
2015-01-01	11.490