Year	Percent
1975-01-01	4.776110000000000
1976-01-01	6.543780000000000
1977-01-01	8.578600000000000
1978-01-01	9.636289999999999
1979-01-01	9.511510000000001
1980-01-01	10.538400000000000
1981-01-01	12.652100000000000
1982-01-01	15.516100000000000
1983-01-01	16.793800000000000
1984-01-01	15.851600000000000
1985-01-01	17.749600000000000
1986-01-01	18.126100000000000
1987-01-01	19.670400000000000
1988-01-01	25.036400000000000
1989-01-01	29.645600000000000
1990-01-01	29.801600000000000
1991-01-01	27.013600000000000
1992-01-01	27.214000000000002
1993-01-01	25.742100000000000
1994-01-01	29.662700000000000
1995-01-01	36.683500000000000
1996-01-01	38.517700000000000
1997-01-01	42.693100000000000
1998-01-01	44.361700000000000
1999-01-01	42.156100000000000
2000-01-01	41.603600000000000
2001-01-01	42.047100000000000
2002-01-01	42.268800000000000
2003-01-01	45.152400000000000
2004-01-01	44.841800000000000
2005-01-01	45.227700000000000
2006-01-01	48.037600000000000
2007-01-01	49.339400000000000
2008-01-01	54.881500000000000
2009-01-01	51.625500000000000
2010-01-01	44.678700000000000
2011-01-01	39.413000000000004
2012-01-01	35.671000000000000
2013-01-01	36.014500000000000
2014-01-01	37.428000000000004
2015-01-01	38.875000000000000
2016-01-01	42.347800000000000