Year	Percent
1960-01-01	7.4910700000000000
1961-01-01	7.1722500000000000
1962-01-01	6.9269700000000000
1963-01-01	6.0707800000000000
1964-01-01	5.6537900000000000
1965-01-01	5.1095600000000000
1966-01-01	4.9213200000000000
1967-01-01	4.7774100000000000
1968-01-01	4.8475600000000000
1969-01-01	5.4355600000000000
1970-01-01	5.1310800000000000
1971-01-01	4.6670800000000000
1972-01-01	4.7268800000000000
1973-01-01	4.5420099999999990
1974-01-01	3.9021199999999996
1975-01-01	3.2284800000000000
1976-01-01	2.8406200000000000
1977-01-01	2.9203200000000002
1978-01-01	3.0441000000000000
1979-01-01	3.0163000000000000
1980-01-01	2.9714600000000000
1981-01-01	3.4025600000000000
1982-01-01	4.6535300000000000
1983-01-01	5.6213800000000000
1984-01-01	5.7373199999999995
1985-01-01	5.7494400000000000
1986-01-01	7.4189500000000000
1987-01-01	7.4906500000000000
1988-01-01	5.5995400000000000
1989-01-01	4.5640900000000000
1990-01-01	3.8698800000000000
1991-01-01	3.2194000000000000
1992-01-01	4.0512200000000000
1993-01-01	11.4140000000000010
1994-01-01	14.6644000000000000
1995-01-01	11.2036000000000000
1996-01-01	9.9345800000000000
1997-01-01	8.8187000000000000
1998-01-01	7.3893900000000000
1999-01-01	7.0228899999999990
2000-01-01	6.4222100000000000
2001-01-01	4.7470500000000000
2002-01-01	4.3924600000000000
2003-01-01	4.5590600000000000
2004-01-01	3.5992699999999997
2005-01-01	2.4698400000000000
2006-01-01	3.0518200000000000
2007-01-01	4.4567100000000000
2008-01-01	4.6202100000000000
2009-01-01	3.9149300000000005
2010-01-01	3.0886400000000003
2011-01-01	2.9605300000000000
2012-01-01	2.7546900000000000
2013-01-01	2.5010300000000000
2014-01-01	2.4094700000000002
2015-01-01	2.3445000000000000
2016-01-01	2.4027100000000000