Year	Percent
1980-01-01	2.3533300000000000
1981-01-01	2.9350000000000000
1982-01-01	3.0133300000000000
1983-01-01	2.7366700000000000
1984-01-01	2.7441700000000000
1985-01-01	3.0708300000000000
1986-01-01	2.9091700000000000
1987-01-01	3.2141700000000000
1988-01-01	3.2266700000000000
1989-01-01	2.9991700000000000
1990-01-01	2.6908300000000000
1991-01-01	2.9533300000000000
1992-01-01	3.0833300000000000
1993-01-01	3.0875000000000000
1994-01-01	2.8766700000000003
1995-01-01	2.8650000000000000
1996-01-01	2.8500000000000000
1997-01-01	2.8508299999999998
1998-01-01	2.8375000000000000
1999-01-01	4.1166700000000000
2000-01-01	4.1216700000000000
2001-01-01	4.1283300000000000
2002-01-01	4.4766699999999995
2003-01-01	4.8041700000000000
2004-01-01	4.8966699999999990
2005-01-01	4.8591700000000000
2006-01-01	4.7425000000000000
2007-01-01	4.8008300000000000
2008-01-01	4.9608300000000005
2009-01-01	5.0875000000000000
2010-01-01	5.1741699999999990
2011-01-01	5.2116700000000000
2012-01-01	5.2441699999999996
2013-01-01	5.2400000000000000
2014-01-01	5.2100000000000000
2015-01-01	5.1700000000000000
2016-01-01	5.1600000000000000