Year	Percent
1980-01-01	20.696400000000000
1981-01-01	23.138600000000000
1982-01-01	26.023100000000000
1983-01-01	30.971500000000000
1984-01-01	31.510000000000000
1985-01-01	33.924600000000000
1986-01-01	35.409800000000000
1987-01-01	35.755800000000000
1988-01-01	34.611900000000000
1989-01-01	33.624300000000000
1990-01-01	33.867700000000000
1991-01-01	31.745800000000000
1992-01-01	72.663300000000000
1993-01-01	74.049100000000000
1994-01-01	74.049100000000000
1995-01-01	74.203000000000000
1996-01-01	73.830400000000000
1997-01-01	69.887000000000000
1998-01-01	69.887000000000000
1999-01-01	56.318999999999996
2000-01-01	47.400000000000000
2001-01-01	41.817900000000000
2002-01-01	37.098500000000000
2003-01-01	34.137100000000000
2004-01-01	30.315600000000000
2005-01-01	28.935000000000000
2006-01-01	25.954000000000000
2007-01-01	19.994100000000000
2008-01-01	19.808500000000000
2009-01-01	20.598300000000000
2010-01-01	21.188700000000000
2011-01-01	23.025700000000000
2012-01-01	22.904800000000000
2013-01-01	21.096500000000000
2014-01-01	22.633700000000000
2015-01-01	21.046200000000000
2016-01-01	19.082000000000000