Year	Percent
1960-01-01	8.432530000000000
1961-01-01	7.876500000000000
1962-01-01	8.182120000000000
1963-01-01	8.293700000000000
1964-01-01	8.661940000000000
1965-01-01	10.304600000000000
1966-01-01	12.270100000000000
1967-01-01	12.822600000000000
1968-01-01	12.960400000000000
1969-01-01	15.128300000000000
1970-01-01	12.456900000000000
1971-01-01	13.880900000000000
1972-01-01	15.634100000000000
1973-01-01	16.492700000000000
1974-01-01	14.898300000000000
1975-01-01	16.154800000000000
1976-01-01	19.136300000000000
1977-01-01	21.540800000000000
1978-01-01	28.701900000000000
1979-01-01	27.604900000000000
1980-01-01	24.389100000000000
1981-01-01	27.084500000000000
1982-01-01	29.169200000000000
1983-01-01	37.937400000000000
1984-01-01	43.642300000000000
1985-01-01	46.888300000000000
1986-01-01	47.684000000000000
1987-01-01	47.949500000000000
1988-01-01	47.444700000000000
1989-01-01	44.385700000000000
1990-01-01	39.496400000000000
1991-01-01	41.158400000000000
1992-01-01	44.631300000000000
1993-01-01	42.883800000000000
1994-01-01	37.197400000000000
1995-01-01	37.489500000000000
1996-01-01	36.423900000000000
1997-01-01	38.083800000000000
1998-01-01	41.915100000000000
1999-01-01	40.815700000000000
2000-01-01	37.813100000000000
2001-01-01	38.818000000000005
2002-01-01	39.956500000000000
2003-01-01	33.392500000000000
2004-01-01	30.611100000000000
2005-01-01	29.680300000000000
2006-01-01	31.038800000000000
2007-01-01	30.569100000000000
2008-01-01	26.662500000000000
2009-01-01	38.681000000000000
2010-01-01	33.556200000000000
2011-01-01	28.684000000000000
2012-01-01	34.985700000000000
2013-01-01	40.097200000000000
2014-01-01	42.067300000000000
2015-01-01	48.554300000000000
2016-01-01	54.330500000000000