Year	Percent
1989-01-01	2.6
1990-01-01	2.4
1991-01-01	2.4
1992-01-01	2.5
1993-01-01	2.9
1994-01-01	2.5
1995-01-01	2.1
1996-01-01	2.0
1997-01-01	2.6
1998-01-01	7.0
1999-01-01	6.6
2000-01-01	4.4
2001-01-01	4.0
2002-01-01	3.3
2003-01-01	3.6
2004-01-01	3.7
2005-01-01	3.7
2006-01-01	3.5
2007-01-01	3.2
2008-01-01	3.2
2009-01-01	3.6
2010-01-01	3.7
2011-01-01	3.4