Year	Percent
1973-01-01	18.728100000000000
1974-01-01	15.656500000000000
1975-01-01	21.401800000000000
1976-01-01	22.828300000000000
1977-01-01	26.426800000000000
1978-01-01	26.426800000000000
1979-01-01	31.432700000000000
1980-01-01	35.495400000000000
1981-01-01	33.234800000000000
1982-01-01	26.772100000000000
1983-01-01	24.940600000000000
1984-01-01	26.447000000000000
1985-01-01	26.404000000000000
1986-01-01	26.404000000000000
1987-01-01	26.404000000000000
1988-01-01	25.270100000000000
1989-01-01	26.227800000000000
1990-01-01	23.497400000000000
1991-01-01	21.576000000000000
1992-01-01	22.417800000000000
1993-01-01	19.332500000000000
1994-01-01	18.555300000000000
1995-01-01	16.903300000000000
1996-01-01	14.321800000000000
1997-01-01	15.130000000000000
1998-01-01	16.652200000000000
1999-01-01	16.538500000000000
2000-01-01	20.574700000000000
2001-01-01	26.702100000000000
2002-01-01	26.298000000000002
2003-01-01	29.306200000000000
2004-01-01	32.606400000000000
2005-01-01	35.492100000000000
2006-01-01	39.993100000000000
2007-01-01	43.314100000000000
2008-01-01	47.253400000000000
2009-01-01	50.695600000000000
2010-01-01	52.037600000000000
2011-01-01	52.613300000000000
2012-01-01	56.011900000000000
2013-01-01	52.246600000000000
2014-01-01	54.299600000000000
2015-01-01	67.152000000000000
2016-01-01	70.633800000000000