Year	Percent
1980-01-01	4.1458300000000000
1981-01-01	4.7083300000000000
1982-01-01	3.9583300000000000
1983-01-01	2.2083300000000000
1984-01-01	3.7916700000000000
1985-01-01	3.0833300000000000
1986-01-01	3.6250000000000000
1987-01-01	2.0416700000000000
1988-01-01	2.0833300000000000
1989-01-01	2.7500000000000000
1990-01-01	2.1666700000000000
1991-01-01	1.7291700000000000
1992-01-01	3.2916700000000000
1993-01-01	2.5416700000000000
1994-01-01	2.4375000000000000
1995-01-01	1.6666700000000000
1996-01-01	3.0625000000000000
1997-01-01	3.1250000000000000
1998-01-01	3.7708300000000000
1999-01-01	4.2083300000000000
2000-01-01	4.5416700000000000
2001-01-01	4.7083300000000000
2002-01-01	4.8958300000000000
2003-01-01	4.6041700000000000
2004-01-01	3.4476000000000000
2005-01-01	2.3363600000000000
2006-01-01	1.9377500000000000
2007-01-01	3.3614800000000002
2008-01-01	3.9093100000000000
2009-01-01	3.4021900000000000
2010-01-01	2.6566500000000000
2011-01-01	2.5706900000000004
2012-01-01	2.7324000000000000
2013-01-01	2.7812799999999998
2014-01-01	3.2520800000000000
2015-01-01	3.2896000000000000
2016-01-01	3.0549700000000000