Year	Percent
1960-01-01	13.496900000000000
1961-01-01	12.645600000000000
1962-01-01	12.869000000000002
1963-01-01	14.691900000000000
1964-01-01	16.619600000000000
1965-01-01	18.440800000000000
1966-01-01	19.674900000000000
1967-01-01	21.729400000000000
1968-01-01	21.692500000000000
1969-01-01	22.473500000000000
1970-01-01	20.390300000000000
1971-01-01	21.588900000000000
1972-01-01	23.856500000000000
1973-01-01	21.379500000000000
1974-01-01	16.664600000000000
1975-01-01	15.331200000000000
1976-01-01	17.987300000000000
1977-01-01	20.256900000000000
1978-01-01	20.837400000000000
1979-01-01	21.129700000000000
1980-01-01	20.136400000000000
1981-01-01	19.132800000000000
1982-01-01	19.333700000000000
1983-01-01	21.317300000000000
1984-01-01	20.767900000000000
1985-01-01	20.298600000000000
1986-01-01	21.060600000000000
1987-01-01	21.873700000000000
1988-01-01	20.817600000000000
1989-01-01	19.102700000000000
1990-01-01	17.942300000000000
1991-01-01	17.208300000000000
1992-01-01	18.953500000000000
1993-01-01	22.076300000000000
1994-01-01	22.851200000000000
1995-01-01	22.298300000000000
1996-01-01	23.146800000000000
1997-01-01	25.554700000000000
1998-01-01	26.390500000000000
1999-01-01	24.949300000000000
2000-01-01	24.626500000000000
2001-01-01	24.976300000000000
2002-01-01	27.733300000000000
2003-01-01	29.529200000000000
2004-01-01	30.945900000000000
2005-01-01	32.565700000000000
2006-01-01	31.852300000000000
2007-01-01	32.773700000000000
2008-01-01	33.308300000000000
2009-01-01	28.559700000000000
2010-01-01	29.338700000000000
2011-01-01	27.176600000000000
2012-01-01	29.121300000000000
2013-01-01	30.259900000000000
2014-01-01	30.515600000000000
2015-01-01	30.342900000000000
2016-01-01	32.122300000000000