Year	Percent
1974-01-01	2.46854
1975-01-01	2.22337
1976-01-01	2.63428
1977-01-01	3.45384
1978-01-01	3.84166
1979-01-01	4.33639
1980-01-01	4.12488
1981-01-01	4.86831
1982-01-01	5.48321
1983-01-01	6.17710
1984-01-01	7.96443
1985-01-01	9.73390
1986-01-01	9.73390
1987-01-01	9.73390
1988-01-01	9.73390
1989-01-01	9.73390
1990-01-01	9.73390
1991-01-01	9.73390
1992-01-01	9.73390
1993-01-01	12.50190
1994-01-01	12.25810
1995-01-01	14.60180
1996-01-01	16.67300
1997-01-01	17.66480
1998-01-01	18.08140
1999-01-01	18.21440
2000-01-01	18.90800
2001-01-01	20.62570
2002-01-01	22.51910
2003-01-01	23.04020
2004-01-01	23.86570
2005-01-01	25.30060
2006-01-01	26.62380
2007-01-01	27.71160
2008-01-01	29.35010
2009-01-01	30.81460
2010-01-01	33.13770
2011-01-01	36.19520
2012-01-01	36.87500
2013-01-01	37.17350
2014-01-01	37.75680
2015-01-01	38.54240
2016-01-01	39.21670