Year	Percent
1962-01-01	11.500000000000000
1963-01-01	11.451200000000000
1964-01-01	10.967700000000000
1965-01-01	11.478100000000000
1966-01-01	11.478100000000000
1967-01-01	11.478100000000000
1968-01-01	11.478100000000000
1969-01-01	16.499600000000000
1970-01-01	19.506900000000000
1971-01-01	19.127400000000000
1972-01-01	17.993600000000000
1973-01-01	19.393000000000000
1974-01-01	24.705100000000000
1975-01-01	27.688200000000000
1976-01-01	29.490200000000000
1977-01-01	31.380700000000000
1978-01-01	32.393400000000000
1979-01-01	34.046400000000000
1980-01-01	31.623500000000000
1981-01-01	38.569600000000000
1982-01-01	46.674700000000000
1983-01-01	46.005600000000000
1984-01-01	48.247200000000000
1985-01-01	46.118600000000000
1986-01-01	42.611100000000000
1987-01-01	44.334600000000000
1988-01-01	34.454300000000000
1989-01-01	31.019600000000000
1990-01-01	32.485800000000000
1991-01-01	32.868100000000000
1992-01-01	30.472800000000000
1993-01-01	30.768100000000000
1994-01-01	24.693300000000000
1995-01-01	25.354100000000000
1996-01-01	23.970600000000000
1997-01-01	20.917600000000000
1998-01-01	23.149200000000000
1999-01-01	22.029600000000000
2000-01-01	25.311500000000000
2001-01-01	26.675900000000000
2002-01-01	24.123100000000000
2003-01-01	26.076400000000000
2004-01-01	27.650300000000000
2005-01-01	29.434000000000000
2006-01-01	30.849500000000000
2007-01-01	34.146700000000000
2008-01-01	36.291500000000000
2009-01-01	38.266999999999996
2010-01-01	41.226400000000000
2011-01-01	43.535900000000000
2012-01-01	43.459300000000000
2013-01-01	44.259100000000000
2014-01-01	45.457300000000000
2015-01-01	49.145000000000000
2016-01-01	52.472000000000000