Year	Percent
1964-01-01	11.0993000000000000
1965-01-01	10.2461000000000000
1966-01-01	9.8774699999999990
1967-01-01	10.8102000000000000
1968-01-01	16.1313000000000000
1969-01-01	16.1313000000000000
1970-01-01	16.1313000000000000
1971-01-01	16.1313000000000000
1972-01-01	16.1313000000000000
1973-01-01	34.7287000000000000
1974-01-01	38.8986000000000000
1975-01-01	44.1468000000000000
1976-01-01	47.2422000000000000
1977-01-01	46.3387000000000000
1978-01-01	51.0529000000000000
1979-01-01	48.0058000000000000
1980-01-01	45.1290000000000000
1981-01-01	49.1539999999999960
1982-01-01	58.4538000000000000
1983-01-01	61.8510000000000060
1984-01-01	62.2872000000000000
1985-01-01	64.0912000000000000
1986-01-01	68.2766000000000000
1987-01-01	67.6265000000000000
1988-01-01	65.1709000000000000
1989-01-01	59.1969000000000000
1990-01-01	51.1798000000000000
1991-01-01	39.9667000000000000
1992-01-01	24.2914000000000000
1993-01-01	6.5337600000000000
1994-01-01	5.9940900000000000
1995-01-01	5.1509700000000000
1996-01-01	4.8105400000000005
1997-01-01	4.3960099999999995
1998-01-01	4.1365800000000000
1999-01-01	4.6028300000000000
2000-01-01	5.0078800000000000
2001-01-01	6.7844100000000000
2002-01-01	9.5870300000000000
2003-01-01	10.7093000000000000
2004-01-01	10.2061000000000000
2005-01-01	10.3006000000000000
2006-01-01	11.1755000000000000
2007-01-01	11.7305000000000000
2008-01-01	11.8444000000000000
2009-01-01	15.2053000000000000
2010-01-01	14.3197000000000000
2011-01-01	13.1412000000000000
2012-01-01	13.4287000000000000
2013-01-01	15.1214000000000000
2014-01-01	17.1355000000000000
2015-01-01	20.3099000000000000
2016-01-01	22.0750000000000000