Year	Percent
1960-01-01	1.4754800000000000
1961-01-01	1.5475299999999999
1962-01-01	1.4648800000000000
1963-01-01	1.4822500000000000
1964-01-01	1.5342100000000000
1965-01-01	1.8199800000000000
1966-01-01	2.2312400000000000
1967-01-01	2.5393100000000000
1968-01-01	2.7458000000000000
1969-01-01	2.5957900000000000
1970-01-01	2.9003400000000004
1971-01-01	2.8649700000000000
1972-01-01	3.0525900000000004
1973-01-01	4.1369500000000000
1974-01-01	5.7438500000000000
1975-01-01	6.8606899999999990
1976-01-01	7.3286600000000000
1977-01-01	8.9105300000000000
1978-01-01	10.0157000000000000
1979-01-01	10.6379000000000000
1980-01-01	10.3148000000000000
1981-01-01	10.2309000000000000
1982-01-01	10.4818000000000000
1983-01-01	10.1036000000000000
1984-01-01	9.2476300000000010
1985-01-01	8.5984500000000000
1986-01-01	7.8809100000000010
1987-01-01	14.9810000000000000
1988-01-01	26.0533000000000000
1989-01-01	34.2973000000000000
1990-01-01	33.1460000000000000
1991-01-01	33.0022000000000000
1992-01-01	38.0245000000000000
1993-01-01	29.5498000000000000
1994-01-01	11.7301000000000000
1995-01-01	10.1781000000000000
1996-01-01	11.2354000000000000
1997-01-01	13.0954000000000000
1998-01-01	13.5250000000000000
1999-01-01	13.3145000000000000
2000-01-01	13.7402000000000000
2001-01-01	13.9922000000000000
2002-01-01	14.7207000000000000
2003-01-01	15.9356000000000000
2004-01-01	14.0442000000000000
2005-01-01	12.6477000000000000
2006-01-01	12.2090000000000010
2007-01-01	11.4133000000000000
2008-01-01	12.2167000000000000
2009-01-01	12.7826000000000000
2010-01-01	13.4781000000000000
2011-01-01	12.8814000000000000
2012-01-01	15.3291000000000000
2013-01-01	17.2040000000000000
2014-01-01	17.8265000000000000
2015-01-01	17.3744000000000000
2016-01-01	16.3306000000000000