Year	Percent
1974-01-01	0.5135860000000000
1975-01-01	1.1770900000000000
1976-01-01	2.0289200000000003
1977-01-01	1.8555900000000000
1978-01-01	2.1463500000000000
1979-01-01	1.7439200000000001
1980-01-01	2.1994900000000000
1981-01-01	2.1465900000000000
1982-01-01	2.1323900000000000
1983-01-01	2.1255200000000000
1984-01-01	1.9869700000000001
1985-01-01	2.6810800000000000
1986-01-01	2.6003200000000000
1987-01-01	2.3374200000000003
1988-01-01	2.3578600000000000
1989-01-01	2.2950200000000000
1990-01-01	2.4851600000000000
1991-01-01	2.8939900000000000
1992-01-01	2.9255500000000000
1993-01-01	2.9937200000000000
1994-01-01	2.9359300000000000
1995-01-01	2.9931799999999997
1996-01-01	2.9704700000000000
1997-01-01	3.2202300000000000
1998-01-01	2.9305900000000000
1999-01-01	3.6164300000000003
2000-01-01	4.9894200000000000
2001-01-01	6.2464800000000000
2002-01-01	6.4586700000000000
2003-01-01	7.4491300000000000
2004-01-01	7.8803199999999990
2005-01-01	9.0596500000000000
2006-01-01	9.8864300000000000
2007-01-01	10.5613000000000000
2008-01-01	10.9838000000000000
2009-01-01	10.5377000000000000
2010-01-01	11.4116000000000000
2011-01-01	11.2149000000000000
2012-01-01	11.0811000000000000
2013-01-01	11.9681000000000000
2014-01-01	12.6046000000000000
2015-01-01	14.1419000000000000
2016-01-01	13.7285000000000000
2017-01-01	13.6656000000000000