Year	Percent
1973-01-01	6.4371500000000000
1974-01-01	7.2458300000000010
1975-01-01	6.9619200000000000
1976-01-01	7.2722399999999990
1977-01-01	8.0150000000000000
1978-01-01	8.8563700000000000
1979-01-01	7.6090300000000010
1980-01-01	7.4005399999999995
1981-01-01	6.8602200000000000
1982-01-01	6.4496400000000005
1983-01-01	6.3934900000000000
1984-01-01	5.1830000000000000
1985-01-01	4.6771000000000000
1986-01-01	3.5477000000000000
1987-01-01	3.0307000000000000
1988-01-01	2.9164600000000000
1989-01-01	2.9001099999999997
1990-01-01	2.9168000000000000
1991-01-01	2.1438900000000003
1992-01-01	2.3183200000000000
1993-01-01	2.8713700000000000
1994-01-01	3.2045900000000000
1995-01-01	2.9510000000000000
1996-01-01	2.7370400000000004
1997-01-01	3.0529400000000000
1998-01-01	3.3655800000000005
1999-01-01	4.6705800000000000
2000-01-01	5.0460500000000000
2001-01-01	5.3923600000000000
2002-01-01	6.0001800000000000
2003-01-01	6.1216099999999996
2004-01-01	6.4528700000000000
2005-01-01	7.6331399999999990
2006-01-01	7.0503300000000010
2007-01-01	7.2410200000000000
2008-01-01	8.9966700000000000
2009-01-01	11.0979999999999990
2010-01-01	11.4499000000000000
2011-01-01	11.5199000000000000
2012-01-01	10.9460000000000000
2013-01-01	10.4377000000000000
2014-01-01	11.9189000000000000
2015-01-01	14.5699000000000000
2016-01-01	14.4877000000000000