Year	Percent
1980-01-01	48.271050000000000
1981-01-01	48.282550000000000
1982-01-01	41.852820000000000
1983-01-01	43.297860000000000
1984-01-01	44.748660000000000
1985-01-01	50.141070000000000
1986-01-01	54.189680000000000
1987-01-01	58.137760000000000
1988-01-01	61.819950000000000
1989-01-01	64.091709999999990
1990-01-01	69.692890000000000
1991-01-01	30.922859999999996
1992-01-01	30.922859999999996
1993-01-01	30.922859999999996
1994-01-01	30.922859999999996
1995-01-01	30.922859999999996
1996-01-01	4.250248000000000
1997-01-01	8.073012000000000
1998-01-01	8.722853000000000
1999-01-01	8.388668000000000
2000-01-01	6.382745000000000
2001-01-01	6.682213000000001
2002-01-01	8.341728999999999
2003-01-01	10.598120000000000
2004-01-01	13.236520000000000
2005-01-01	16.575300000000000
2006-01-01	21.217520000000000
2007-01-01	27.728209999999997
2008-01-01	32.982440000000004
2009-01-01	39.236220000000000
2010-01-01	38.696280000000000
2011-01-01	38.557240000000000
2012-01-01	37.798170000000000
2013-01-01	35.220310000000000
2014-01-01	31.999709999999997