Year	Percent
1973-01-01	63.9501
1974-01-01	65.6136
1975-01-01	64.2768
1976-01-01	62.6628
1977-01-01	63.5727
1978-01-01	63.3063
1979-01-01	63.2476
1980-01-01	63.5709
1981-01-01	60.4055
1982-01-01	61.3298
1983-01-01	60.2727
1984-01-01	61.0183
1985-01-01	63.6925
1986-01-01	65.7633
1987-01-01	66.1694
1988-01-01	64.2747
1989-01-01	62.7403
1990-01-01	60.5085
1991-01-01	58.2154
1992-01-01	54.9717
1993-01-01	53.2897
1994-01-01	51.8918
1995-01-01	52.2507
1996-01-01	52.5589
1997-01-01	52.5111
1998-01-01	52.7984
1999-01-01	52.7257
2000-01-01	53.3239
2001-01-01	55.2533
2002-01-01	55.6693
2003-01-01	55.7228
2004-01-01	56.1050
2005-01-01	57.6341
2006-01-01	59.8442
2007-01-01	62.7639
2008-01-01	68.2308
2009-01-01	66.7732
2010-01-01	60.5677
2011-01-01	59.4118
2012-01-01	58.3919
2013-01-01	58.3872
2014-01-01	58.6761
2015-01-01	59.9259
2016-01-01	62.6747