Year	Percent
1960-01-01	1.9736799999999999
1961-01-01	2.0108700000000000
1962-01-01	2.5714300000000000
1963-01-01	3.0272700000000000
1964-01-01	2.4565200000000003
1965-01-01	1.9579099999999998
1966-01-01	2.9595400000000000
1967-01-01	3.9616100000000000
1968-01-01	4.9336500000000000
1969-01-01	5.1061700000000000
1970-01-01	5.7052400000000000
1971-01-01	6.0370700000000000
1972-01-01	6.1762700000000000
1973-01-01	8.4251899999999990
1974-01-01	10.2335000000000000
1975-01-01	11.4530000000000000
1976-01-01	12.0622000000000000
1977-01-01	13.0970000000000010
1978-01-01	13.2492000000000000
1979-01-01	11.4423000000000000
1980-01-01	12.9261000000000000
1981-01-01	15.2443000000000000
1982-01-01	16.8737000000000000
1983-01-01	15.6019000000000000
1984-01-01	15.7473000000000000
1985-01-01	16.9149000000000000
1986-01-01	15.3828000000000000
1987-01-01	16.2385000000000000
1988-01-01	16.4805000000000000
1989-01-01	15.4011000000000000
1990-01-01	14.4158000000000000
1991-01-01	14.7345000000000000
1992-01-01	14.7345000000000000
1993-01-01	14.7345000000000000
1994-01-01	14.7345000000000000
1995-01-01	14.7345000000000000
1996-01-01	14.7345000000000000
1997-01-01	14.7345000000000000
1998-01-01	14.7345000000000000
1999-01-01	14.7345000000000000
2000-01-01	14.7345000000000000
2001-01-01	14.7345000000000000
2002-01-01	14.7345000000000000
2003-01-01	14.7345000000000000
2004-01-01	14.7345000000000000
2005-01-01	17.8438000000000000
2006-01-01	13.3146000000000000
2007-01-01	14.5586000000000000
2008-01-01	16.5252000000000000
2009-01-01	18.8652000000000000
2010-01-01	17.3460000000000000
2011-01-01	16.9500000000000000
2012-01-01	18.4652000000000000