Year	Percent
1968-01-01	0.01155200000000000
1969-01-01	0.01065900000000000
1970-01-01	0.01007100000000000
1971-01-01	0.05943600000000000
1972-01-01	0.19091100000000000
1973-01-01	0.23249499999999998
1974-01-01	0.43940100000000004
1975-01-01	0.87375500000000000
1976-01-01	1.67028000000000000
1977-01-01	2.09957000000000000
1978-01-01	2.16634000000000000
1979-01-01	2.14749000000000030
1980-01-01	2.05977000000000000
1981-01-01	2.56659000000000000
1982-01-01	3.76663000000000000
1983-01-01	4.78435000000000000
1984-01-01	6.03681000000000000
1985-01-01	7.08811000000000000
1986-01-01	6.28179000000000000
1987-01-01	6.65932000000000000
1988-01-01	7.06298999999999900
1989-01-01	7.75606999999999900
1990-01-01	7.71920000000000000
1991-01-01	9.07701000000000100
1992-01-01	8.76750000000000000
1993-01-01	9.86080000000000000
1994-01-01	10.68970000000000000
1995-01-01	10.08620000000000000
1996-01-01	10.40150000000000000
1997-01-01	11.31299999999999900
1998-01-01	13.51400000000000100
1999-01-01	15.97910000000000000
2000-01-01	21.00260000000000000
2001-01-01	26.39020000000000000
2002-01-01	31.73600000000000000
2003-01-01	36.70960000000000000
2004-01-01	40.05130000000000000
2005-01-01	40.03610000000000000
2006-01-01	49.81040000000000000
2007-01-01	54.03300000000000000
2008-01-01	50.55070000000000000
2009-01-01	63.13070000000000000
2010-01-01	64.74180000000000000
2011-01-01	61.70120000000000000
2012-01-01	67.41770000000000000
2013-01-01	65.80290000000000000
2014-01-01	59.19330000000000000
2015-01-01	61.57960000000000000
2016-01-01	61.02870000000000000