Year	Percent
1971-01-01	31.647700000000000
1972-01-01	29.525300000000000
1973-01-01	30.230400000000000
1974-01-01	29.020500000000000
1975-01-01	26.945999999999998
1976-01-01	24.594300000000000
1977-01-01	24.095500000000000
1978-01-01	23.205400000000000
1979-01-01	20.274000000000000
1980-01-01	22.301600000000000
1981-01-01	25.160200000000000
1982-01-01	23.054400000000000
1983-01-01	22.776600000000000
1984-01-01	23.569400000000000
1985-01-01	23.576100000000000
1986-01-01	26.191999999999997
1987-01-01	27.185700000000000
1988-01-01	29.276000000000000
1989-01-01	31.456000000000000
1990-01-01	32.361900000000000
1991-01-01	35.190200000000000
1992-01-01	37.702300000000000
1993-01-01	41.071100000000000
1994-01-01	50.127500000000000
1995-01-01	59.476500000000000
1996-01-01	65.805300000000000
1997-01-01	67.131000000000000
1998-01-01	69.223400000000000
1999-01-01	77.760200000000000
2000-01-01	81.119500000000000
2001-01-01	86.598300000000000
2002-01-01	90.315800000000000
2003-01-01	97.433400000000000
2004-01-01	84.171000000000000
2005-01-01	80.115000000000000
2006-01-01	74.801300000000000
2007-01-01	59.503000000000000
2008-01-01	50.828300000000000
2009-01-01	50.072900000000000
2010-01-01	53.742900000000000
2011-01-01	53.943400000000000
2012-01-01	47.868600000000000
2013-01-01	48.234300000000000
2014-01-01	57.098200000000000
2015-01-01	61.887300000000000
2016-01-01	62.556500000000000