Year	Percent
1974-01-01	5.155069999999999
1975-01-01	11.770100000000000
1976-01-01	11.376400000000000
1977-01-01	12.191300000000000
1978-01-01	14.190300000000000
1979-01-01	16.892500000000000
1980-01-01	14.213500000000000
1981-01-01	17.980700000000000
1982-01-01	19.153800000000000
1983-01-01	28.814900000000000
1984-01-01	30.639600000000000
1985-01-01	45.550900000000000
1986-01-01	37.209800000000000
1987-01-01	44.261100000000000
1988-01-01	50.526900000000000
1989-01-01	48.750000000000000
1990-01-01	40.451200000000000
1991-01-01	34.228300000000000
1992-01-01	26.790100000000000
1993-01-01	42.675200000000000
1994-01-01	42.553900000000000
1995-01-01	44.431400000000000
1996-01-01	30.910100000000000
1997-01-01	25.930999999999997
1998-01-01	22.341200000000000
1999-01-01	23.010300000000000
2000-01-01	27.576999999999998
2001-01-01	29.135300000000000
2002-01-01	39.425300000000000
2003-01-01	39.502500000000000
2004-01-01	44.928700000000000
2005-01-01	36.974800000000000
2006-01-01	39.847600000000000
2007-01-01	38.510900000000000
2008-01-01	38.847300000000000
2009-01-01	56.676000000000000
2010-01-01	59.303100000000000
2011-01-01	47.282400000000000
2012-01-01	40.065900000000000
2013-01-01	39.551100000000000
2014-01-01	25.791700000000000
2015-01-01	31.959700000000000