Year	Percent
1976-01-01	11.0504000000000000
1977-01-01	10.4057000000000000
1978-01-01	11.3501000000000000
1979-01-01	14.3887000000000000
1980-01-01	16.7705000000000000
1981-01-01	22.1509000000000000
1982-01-01	24.8541000000000000
1983-01-01	27.0308000000000000
1984-01-01	26.9840000000000000
1985-01-01	29.7978000000000000
1986-01-01	30.2007000000000000
1987-01-01	31.3580000000000000
1988-01-01	29.9540000000000000
1989-01-01	31.5058000000000000
1990-01-01	36.2106000000000000
1991-01-01	40.0833000000000000
1992-01-01	43.0750000000000000
1993-01-01	34.3666000000000000
1994-01-01	20.3362000000000000
1995-01-01	14.6841000000000000
1996-01-01	13.9360000000000000
1997-01-01	13.7929000000000000
1998-01-01	12.3135000000000000
1999-01-01	10.3334000000000000
2000-01-01	12.3368000000000000
2001-01-01	14.7787000000000000
2002-01-01	15.0127000000000000
2003-01-01	14.3661000000000000
2004-01-01	13.5125000000000000
2005-01-01	12.1819000000000000
2006-01-01	10.3911000000000000
2007-01-01	8.7285800000000010
2008-01-01	8.0083000000000000
2009-01-01	7.6934400000000000
2010-01-01	7.4681100000000000
2011-01-01	6.8343300000000005
2012-01-01	6.3908900000000000
2013-01-01	6.1453000000000000
2014-01-01	6.0372500000000000
2015-01-01	5.7545699999999990
2016-01-01	5.3408000000000000