Year	Percent
1960-01-01	41.50080000000000
1961-01-01	38.68630000000000
1962-01-01	38.16270000000000
1963-01-01	41.11060000000000
1964-01-01	45.40220000000000
1965-01-01	47.69590000000000
1966-01-01	49.53740000000000
1967-01-01	49.39260000000000
1968-01-01	51.40550000000000
1969-01-01	53.26390000000000
1970-01-01	50.21970000000000
1971-01-01	54.45430000000000
1972-01-01	58.34440000000000
1973-01-01	61.45570000000000
1974-01-01	62.82840000000000
1975-01-01	55.55280000000000
1976-01-01	49.39870000000000
1977-01-01	48.54450000000000
1978-01-01	46.70050000000000
1979-01-01	53.06720000000000
1980-01-01	61.92330000000000
1981-01-01	69.74490000000000
1982-01-01	73.63210000000000
1983-01-01	73.19730000000000
1984-01-01	76.04140000000000
1985-01-01	77.54480000000000
1986-01-01	73.57050000000000
1987-01-01	72.02730000000000
1988-01-01	69.28890000000000
1989-01-01	68.17520000000000
1990-01-01	64.83270000000000
1991-01-01	65.97830000000000
1992-01-01	71.25840000000000
1993-01-01	76.94990000000000
1994-01-01	78.12850000000000
1995-01-01	79.07810000000000
1996-01-01	79.70110000000000
1997-01-01	78.10250000000000
1998-01-01	76.30530000000000
1999-01-01	80.99730000000000
2000-01-01	85.69740000000000
2001-01-01	83.90360000000000
2002-01-01	80.54710000000000
2003-01-01	78.92300000000000
2004-01-01	77.50830000000000
2005-01-01	78.08060000000000
2006-01-01	79.39250000000000
2007-01-01	78.70260000000000
2008-01-01	84.44560000000000
2009-01-01	86.65280000000000
2010-01-01	83.11040000000000
2011-01-01	86.65299999999999
2012-01-01	86.31310000000000
2013-01-01	81.29370000000000
2014-01-01	80.98130000000000
2015-01-01	80.18230000000000
2016-01-01	82.56110000000000