Year	Percent
1970-01-01	2.4242400000000000
1971-01-01	2.2586500000000000
1972-01-01	2.1855700000000002
1973-01-01	2.2405200000000000
1974-01-01	1.8418500000000000
1975-01-01	1.9364900000000000
1976-01-01	1.8713700000000000
1977-01-01	1.7074200000000002
1978-01-01	1.7888800000000000
1979-01-01	1.7906400000000002
1980-01-01	0.8940809999999999
1981-01-01	0.9864280000000001
1982-01-01	0.7732190000000000
1983-01-01	0.6799620000000000
1984-01-01	0.7678630000000000
1985-01-01	0.5749250000000000
1986-01-01	0.6939440000000000
1987-01-01	1.6454900000000001
1988-01-01	1.7527800000000000
1989-01-01	1.5875100000000000
1990-01-01	1.8731600000000000
1991-01-01	2.2495000000000000
1992-01-01	2.7935800000000000
1993-01-01	2.7050300000000000
1994-01-01	2.6588600000000000
1995-01-01	2.6923400000000000
1996-01-01	2.8193900000000003
1997-01-01	3.0204400000000002
1998-01-01	3.0179600000000000
1999-01-01	3.2768000000000000
2000-01-01	3.6264600000000000
2001-01-01	4.1695400000000005
2002-01-01	3.9456400000000000
2003-01-01	3.9849200000000000
2004-01-01	3.7135900000000000
2005-01-01	2.4236100000000000
2006-01-01	2.0569000000000000
2007-01-01	3.0654700000000000
2008-01-01	2.1956599999999997
2009-01-01	2.5817500000000000
2010-01-01	1.8349400000000002
2011-01-01	3.1601900000000000
2012-01-01	2.6009300000000000
2013-01-01	2.3483400000000003
2014-01-01	2.3504600000000000
2015-01-01	2.3628600000000000
2016-01-01	2.3916100000000000
2017-01-01	2.3296099999999997