Year	Percent
1972-01-01	46.35700000000000
1973-01-01	62.71970000000000
1974-01-01	74.54460000000000
1975-01-01	96.61480000000000
1976-01-01	95.94030000000000
1977-01-01	78.79750000000000
1978-01-01	71.18310000000000
1979-01-01	67.69570000000000
1980-01-01	70.05420000000000
1981-01-01	79.38920000000000
1982-01-01	73.90670000000000
1983-01-01	68.38930000000000
1984-01-01	66.21910000000000
1985-01-01	59.33590000000000
1986-01-01	57.58880000000000
1987-01-01	58.13190000000000
1988-01-01	52.42390000000000
1989-01-01	50.45399999999999
1990-01-01	57.68810000000000
1991-01-01	62.28840000000000
1992-01-01	68.08920000000000
1993-01-01	75.23770000000000
1994-01-01	74.86190000000000
1995-01-01	69.43640000000000
1996-01-01	60.16030000000000
1997-01-01	51.23720000000000
1998-01-01	46.52290000000000
1999-01-01	49.70750000000000
2000-01-01	58.56570000000000
2001-01-01	59.68590000000000
2002-01-01	62.82070000000000
2003-01-01	68.76580000000000
2004-01-01	71.80070000000000
2005-01-01	74.10400000000000
2006-01-01	58.89320000000000
2007-01-01	49.42860000000000
2008-01-01	49.55420000000000
2009-01-01	53.66090000000000
2010-01-01	57.74710000000000
2011-01-01	62.51540000000000
2012-01-01	70.05410000000000
2013-01-01	75.60450000000000
2014-01-01	81.01010000000000
2015-01-01	79.59410000000000
2016-01-01	76.91700000000000