Year	Percent
1971-01-01	0.0790800000000000
1972-01-01	0.4604000000000000
1973-01-01	0.7146570000000000
1974-01-01	0.6238140000000000
1975-01-01	0.7886010000000000
1976-01-01	1.2345000000000000
1977-01-01	3.2337000000000000
1978-01-01	3.7076599999999997
1979-01-01	2.9641700000000000
1980-01-01	2.0647599999999997
1981-01-01	2.1804799999999998
1982-01-01	3.3530800000000003
1983-01-01	3.4359599999999997
1984-01-01	2.6242300000000000
1985-01-01	2.3596900000000000
1986-01-01	3.1906600000000000
1987-01-01	2.9195000000000000
1988-01-01	1.2711299999999999
1989-01-01	0.8884320000000000
1990-01-01	15.3268000000000000
1991-01-01	13.5552000000000000
1992-01-01	12.6091000000000000
1993-01-01	10.9889000000000000
1994-01-01	11.7714000000000000
1995-01-01	18.0420000000000000
1996-01-01	18.0247000000000000
1997-01-01	15.0239000000000000
1998-01-01	14.9709999999999980
1999-01-01	14.3870000000000000
2000-01-01	12.5110000000000000
2001-01-01	11.1847000000000000
2002-01-01	10.8714000000000000
2003-01-01	10.0811000000000000
2004-01-01	10.3402000000000000
2005-01-01	9.5404200000000000
2006-01-01	8.7774399999999990
2007-01-01	8.5173399999999990
2008-01-01	7.4658000000000000
2009-01-01	10.3904000000000000
2010-01-01	9.7208800000000010
2011-01-01	10.1804000000000000
2012-01-01	12.2098000000000000
2013-01-01	13.7157000000000000
2014-01-01	14.8386000000000000
2015-01-01	18.1152000000000000
2016-01-01	22.8180000000000000