Year	Percent
1972-01-01	1.8750700000000000
1973-01-01	2.3553200000000000
1974-01-01	1.7443700000000000
1975-01-01	2.1124099999999997
1976-01-01	4.4574800000000000
1977-01-01	7.0267899999999990
1978-01-01	7.2247600000000010
1979-01-01	5.9281500000000000
1980-01-01	4.6076000000000000
1981-01-01	3.8174400000000000
1982-01-01	3.4579600000000000
1983-01-01	2.9310400000000003
1984-01-01	2.5030500000000000
1985-01-01	2.8476900000000000
1986-01-01	3.4896300000000005
1987-01-01	4.1822900000000000
1988-01-01	3.4573600000000000
1989-01-01	1.8801200000000000
1990-01-01	2.0745700000000000
1991-01-01	1.7966099999999998
1992-01-01	1.3996400000000000
1993-01-01	1.6011300000000000
1994-01-01	1.8975900000000000
1995-01-01	1.4131300000000000
1996-01-01	3.3816100000000000
1997-01-01	5.0427300000000010
1998-01-01	8.8498500000000000
1999-01-01	11.9560000000000000
2000-01-01	15.1929000000000000
2001-01-01	23.3810000000000000
2002-01-01	21.8607000000000000
2003-01-01	27.9192000000000000
2004-01-01	30.5722000000000000
2005-01-01	29.9668000000000000
2006-01-01	29.0303000000000000
2007-01-01	26.5400000000000000
2008-01-01	25.7406000000000000
2009-01-01	25.8092000000000000
2010-01-01	23.0457000000000000
2011-01-01	23.1074000000000000
2012-01-01	27.2688000000000000
2013-01-01	31.4617000000000000
2014-01-01	31.0045000000000000
2015-01-01	29.4063000000000000
2016-01-01	28.3346000000000000