Year	Percent
1976-01-01	10.1
1977-01-01	11.5
1978-01-01	11.4
1979-01-01	10.2
1980-01-01	10.4
1981-01-01	10.5
1982-01-01	15.9
1983-01-01	17.3
1984-01-01	15.8
1985-01-01	14.1
1986-01-01	13.3
1987-01-01	12.0
1988-01-01	10.3
1989-01-01	9.4
1990-01-01	10.9
1991-01-01	14.9
1992-01-01	15.6
1993-01-01	15.2
1994-01-01	13.5
1995-01-01	12.0
1996-01-01	12.1
1997-01-01	12.5
1998-01-01	11.6
1999-01-01	10.8
2000-01-01	9.4
2001-01-01	9.6
2002-01-01	10.1
2003-01-01	10.0
2004-01-01	9.6
2005-01-01	8.9
2006-01-01	8.2
2007-01-01	7.9
2008-01-01	8.0
2009-01-01	11.2
2010-01-01	10.7
2011-01-01	10.1
2012-01-01	10.0