Year	Percent
1960-01-01	3.3670000000000000
1961-01-01	3.3609300000000000
1962-01-01	3.6718800000000003
1963-01-01	4.2148800000000000
1964-01-01	4.4625400000000000
1965-01-01	5.1180000000000000
1966-01-01	5.1180000000000000
1967-01-01	5.1180000000000000
1968-01-01	5.1180000000000000
1969-01-01	9.7022000000000000
1970-01-01	11.7855000000000000
1971-01-01	11.4684000000000000
1972-01-01	10.4779000000000000
1973-01-01	11.4929000000000000
1974-01-01	16.5024000000000000
1975-01-01	18.6725000000000000
1976-01-01	18.7738000000000000
1977-01-01	20.3543000000000000
1978-01-01	21.4784000000000000
1979-01-01	22.7159000000000000
1980-01-01	20.1534000000000000
1981-01-01	20.8690000000000000
1982-01-01	23.7373000000000000
1983-01-01	26.0944000000000000
1984-01-01	32.2371000000000000
1985-01-01	33.1572000000000000
1986-01-01	30.5491000000000000
1987-01-01	31.3909000000000000
1988-01-01	26.2408000000000000
1989-01-01	26.0595000000000000
1990-01-01	26.6006000000000000
1991-01-01	25.7502000000000000
1992-01-01	24.3496000000000000
1993-01-01	26.5149000000000000
1994-01-01	20.0859000000000000
1995-01-01	16.9486000000000000
1996-01-01	15.5444000000000000
1997-01-01	14.1820000000000000
1998-01-01	15.4454000000000000
1999-01-01	13.9010000000000000
2000-01-01	15.2667000000000000
2001-01-01	16.3703000000000000
2002-01-01	16.2826000000000000
2003-01-01	19.9302000000000000
2004-01-01	21.4603000000000000
2005-01-01	22.7425000000000000
2006-01-01	23.4469000000000000
2007-01-01	24.7232000000000000
2008-01-01	26.5266000000000000
2009-01-01	28.8115000000000000
2010-01-01	30.7032000000000000
2011-01-01	32.3589000000000000
2012-01-01	33.9607000000000000
2013-01-01	35.9712000000000000
2014-01-01	37.9683000000000000
2015-01-01	40.5599000000000000
2016-01-01	42.7742000000000000