Year	Percent
1960-01-01	6.883550000000000
1961-01-01	6.604000000000000
1962-01-01	6.984240000000000
1963-01-01	7.888130000000000
1964-01-01	8.679250000000000
1965-01-01	10.367500000000000
1966-01-01	11.536000000000000
1967-01-01	11.325600000000000
1968-01-01	10.252500000000000
1969-01-01	9.225070000000000
1970-01-01	11.982700000000000
1971-01-01	10.616400000000000
1972-01-01	10.065900000000000
1973-01-01	10.385200000000000
1974-01-01	10.461600000000000
1975-01-01	10.588500000000000
1976-01-01	11.299600000000000
1977-01-01	10.850300000000000
1978-01-01	10.893900000000000
1979-01-01	12.581700000000000
1980-01-01	12.216400000000000
1981-01-01	14.362800000000000
1982-01-01	16.261000000000000
1983-01-01	20.789100000000000
1984-01-01	24.719400000000000
1985-01-01	20.167700000000000
1986-01-01	16.295200000000000
1987-01-01	14.579500000000000
1988-01-01	16.699200000000000
1989-01-01	5.939769999999999
1990-01-01	5.682320000000000
1991-01-01	3.418500000000000
1992-01-01	5.739719999999999
1993-01-01	6.142000000000000
1994-01-01	8.780420000000000
1995-01-01	11.240700000000000
1996-01-01	14.633600000000000
1997-01-01	20.184200000000000
1998-01-01	27.726000000000000
1999-01-01	25.621300000000000
2000-01-01	25.805900000000000
2001-01-01	25.097200000000000
2002-01-01	26.487300000000000
2003-01-01	27.711200000000000
2004-01-01	27.713100000000000
2005-01-01	27.204700000000000
2006-01-01	26.039300000000000
2007-01-01	24.946900000000000
2008-01-01	24.358300000000000
2009-01-01	25.683300000000000
2010-01-01	27.289200000000000
2011-01-01	26.841600000000000
2012-01-01	27.005700000000000
2013-01-01	29.414000000000000
2014-01-01	30.449600000000000
2015-01-01	31.657400000000000
2016-01-01	33.601000000000000