Year	Percent
1973-01-01	99.56230000000000
1974-01-01	77.26460000000000
1975-01-01	77.75820000000000
1976-01-01	83.46610000000000
1977-01-01	60.13290000000000
1978-01-01	54.35150000000000
1979-01-01	53.05040000000000
1980-01-01	61.33850000000000
1981-01-01	79.03190000000000
1982-01-01	87.09440000000000
1983-01-01	87.83150000000000
1984-01-01	86.85050000000000
1985-01-01	87.67670000000000
1986-01-01	88.93810000000000
1987-01-01	91.04310000000000
1988-01-01	93.29299999999999
1989-01-01	96.21150000000000
1990-01-01	95.81100000000000
1991-01-01	88.05560000000000
1992-01-01	75.97770000000000
1993-01-01	60.97700000000000
1994-01-01	56.95390000000000
1995-01-01	56.91230000000000
1996-01-01	47.73730000000000
1997-01-01	47.08020000000000
1998-01-01	57.15780000000000
1999-01-01	62.01100000000000
2000-01-01	59.23850000000000
2001-01-01	57.48120000000000
2002-01-01	54.99040000000000
2003-01-01	55.16490000000000
2004-01-01	52.36030000000000
2005-01-01	47.28310000000000
2006-01-01	45.28430000000000
2007-01-01	46.08320000000000
2008-01-01	53.00150000000000
2009-01-01	55.96560000000000
2010-01-01	55.79600000000001
2011-01-01	55.64910000000000
2012-01-01	53.59090000000000
2013-01-01	56.42700000000000
2014-01-01	59.24320000000000
2015-01-01	57.97820000000000
2016-01-01	55.54960000000000