Year	Percent
1960-01-01	6.9005399999999995
1961-01-01	6.8075199999999990
1962-01-01	6.5492000000000000
1963-01-01	6.3537600000000000
1964-01-01	6.0185800000000000
1965-01-01	5.8136300000000000
1966-01-01	5.5441900000000000
1967-01-01	5.4259000000000000
1968-01-01	5.3098300000000010
1969-01-01	5.0565000000000000
1970-01-01	4.9967200000000000
1971-01-01	4.9931700000000000
1972-01-01	5.0404000000000000
1973-01-01	4.8272800000000000
1974-01-01	4.6546400000000006
1975-01-01	4.7279000000000000
1976-01-01	4.4293700000000000
1977-01-01	4.4763400000000000
1978-01-01	4.6783600000000000
1979-01-01	4.6214200000000000
1980-01-01	4.6525700000000000
1981-01-01	4.5332500000000000
1982-01-01	4.2417200000000000
1983-01-01	3.8689199999999997
1984-01-01	3.7310700000000000
1985-01-01	3.3111500000000000
1986-01-01	3.2344500000000000
1987-01-01	3.3690700000000000
1988-01-01	3.2603900000000000
1989-01-01	3.1022400000000000
1990-01-01	2.9622200000000000
1991-01-01	3.0587600000000000
1992-01-01	3.1124400000000003
1993-01-01	3.0814000000000000
1994-01-01	3.0547800000000000
1995-01-01	2.9395800000000000
1996-01-01	2.8484700000000003
1997-01-01	2.9089800000000000
1998-01-01	2.9353100000000000
1999-01-01	3.0082900000000000
2000-01-01	2.9670000000000000
2001-01-01	3.1609500000000000
2002-01-01	3.3517400000000000
2003-01-01	3.2786699999999995
2004-01-01	3.1793099999999996
2005-01-01	3.1748700000000000
2006-01-01	3.1901599999999997
2007-01-01	3.1332800000000000
2008-01-01	2.7793700000000000
2009-01-01	2.7729800000000000
2010-01-01	3.1369400000000000
2011-01-01	3.4339400000000000
2012-01-01	3.7970900000000003
2013-01-01	4.3374000000000000
2014-01-01	4.5465800000000005
2015-01-01	4.6652000000000000
2016-01-01	4.7193600000000000