Year	Percent
1970-01-01	7.8379500000000000
1971-01-01	7.9027199999999995
1972-01-01	8.6745900000000000
1973-01-01	8.3121200000000000
1974-01-01	9.3741300000000010
1975-01-01	10.2415000000000000
1976-01-01	10.1156000000000000
1977-01-01	11.2356000000000000
1978-01-01	12.0958000000000000
1979-01-01	11.9112000000000000
1980-01-01	13.8059000000000000
1981-01-01	17.5982000000000000
1982-01-01	23.1185000000000000
1983-01-01	21.4224000000000000
1984-01-01	16.9139000000000000
1985-01-01	17.4292000000000000
1986-01-01	20.3422000000000000
1987-01-01	23.9843000000000000
1988-01-01	26.3255000000000000
1989-01-01	26.2749000000000000
1990-01-01	24.9710000000000000
1991-01-01	25.3022000000000000
1992-01-01	23.5801000000000000
1993-01-01	21.4891000000000000
1994-01-01	30.9688000000000000
1995-01-01	22.9957000000000000
1996-01-01	25.2786000000000000
1997-01-01	25.0131000000000000
1998-01-01	24.5056000000000000
1999-01-01	27.3634000000000000
2000-01-01	30.1051000000000000
2001-01-01	29.8503000000000000
2002-01-01	30.3148000000000000
2003-01-01	31.2173000000000000
2004-01-01	34.0683000000000000
2005-01-01	31.4448000000000000
2006-01-01	33.4636000000000000
2007-01-01	35.3918000000000000
2008-01-01	34.1998000000000000
2009-01-01	37.2004000000000000
2010-01-01	41.9286000000000000
2011-01-01	38.0898000000000000
2012-01-01	34.6751000000000000
2013-01-01	36.9702000000000000
2014-01-01	38.3460000000000000
2015-01-01	39.6615000000000000
2016-01-01	41.0449000000000000