Year	Percent
1973-01-01	14.125400000000000
1974-01-01	14.448000000000000
1975-01-01	13.766100000000000
1976-01-01	13.744500000000000
1977-01-01	14.365300000000000
1978-01-01	17.042600000000000
1979-01-01	17.599500000000000
1980-01-01	17.453100000000000
1981-01-01	16.445400000000000
1982-01-01	16.562900000000000
1983-01-01	16.086400000000000
1984-01-01	15.924300000000000
1985-01-01	16.147800000000000
1986-01-01	15.521300000000000
1987-01-01	17.139000000000000
1988-01-01	17.181300000000000
1989-01-01	16.688900000000000
1990-01-01	16.672300000000000
1991-01-01	17.525300000000000
1992-01-01	20.001100000000000
1993-01-01	19.779700000000000
1994-01-01	21.026800000000000
1995-01-01	22.490500000000000
1996-01-01	22.565000000000000
1997-01-01	25.500700000000000
1998-01-01	28.062400000000000
1999-01-01	30.233600000000000
2000-01-01	30.313000000000002
2001-01-01	30.087800000000000
2002-01-01	31.371100000000000
2003-01-01	32.558600000000000
2004-01-01	32.314700000000000
2005-01-01	31.393500000000000
2006-01-01	31.087500000000000
2007-01-01	30.365200000000000
2008-01-01	33.206400000000000
2009-01-01	33.149900000000000
2010-01-01	36.915900000000000
2011-01-01	38.912600000000000
2012-01-01	39.670300000000000
2013-01-01	42.046700000000000
2014-01-01	43.776100000000000
2015-01-01	44.252100000000000
2016-01-01	43.810500000000000