Year	Percent
1975-01-01	26.389100000000000
1976-01-01	22.694000000000003
1977-01-01	23.428200000000000
1978-01-01	25.310600000000000
1979-01-01	26.869300000000000
1980-01-01	27.394200000000000
1981-01-01	27.995100000000000
1982-01-01	27.994100000000000
1983-01-01	27.573300000000000
1984-01-01	25.787100000000000
1985-01-01	25.222800000000000
1986-01-01	24.859800000000000
1987-01-01	25.571200000000000
1988-01-01	26.720100000000000
1989-01-01	30.353100000000000
1990-01-01	30.739400000000000
1991-01-01	31.893800000000000
1992-01-01	33.340900000000000
1993-01-01	34.272500000000000
1994-01-01	35.125200000000000
1995-01-01	36.917500000000000
1996-01-01	41.952500000000000
1997-01-01	44.610300000000000
1998-01-01	45.852400000000000
1999-01-01	48.673600000000000
2000-01-01	53.067600000000000
2001-01-01	51.761500000000000
2002-01-01	50.328000000000000
2003-01-01	48.491100000000000
2004-01-01	45.544500000000000
2005-01-01	44.922200000000000
2006-01-01	43.948100000000000
2007-01-01	47.367600000000000
2008-01-01	48.996100000000000
2009-01-01	50.227900000000000
2010-01-01	51.468600000000000
2011-01-01	52.731900000000000
2012-01-01	52.954300000000000
2013-01-01	52.574900000000000
2014-01-01	52.476500000000000
2015-01-01	50.721000000000004
2016-01-01	50.709500000000000