Year	Percent
1973-01-01	15.9385000000000000
1974-01-01	18.3434000000000000
1975-01-01	19.3005000000000000
1976-01-01	15.4356000000000000
1977-01-01	13.3842000000000000
1978-01-01	13.8053000000000000
1979-01-01	11.7922000000000000
1980-01-01	17.0053000000000000
1981-01-01	13.5179999999999990
1982-01-01	13.1918000000000000
1983-01-01	12.9719000000000000
1984-01-01	11.1718000000000000
1985-01-01	9.0243399999999990
1986-01-01	9.4438300000000000
1987-01-01	9.1734100000000000
1988-01-01	8.5642600000000000
1989-01-01	9.1533199999999990
1990-01-01	10.1492000000000000
1991-01-01	10.3337000000000000
1992-01-01	8.5716399999999990
1993-01-01	6.9334000000000000
1994-01-01	6.1880400000000000
1995-01-01	5.8921800000000010
1996-01-01	6.7377800000000000
1997-01-01	6.0808800000000005
1998-01-01	6.1194000000000000
1999-01-01	6.8617200000000000
2000-01-01	7.8930899999999990
2001-01-01	8.0416600000000000
2002-01-01	8.2231300000000010
2003-01-01	8.9271800000000000
2004-01-01	8.8818500000000000
2005-01-01	8.8771200000000000
2006-01-01	8.9564600000000000
2007-01-01	8.9071500000000000
2008-01-01	9.1321500000000000
2009-01-01	8.7328400000000000
2010-01-01	9.3850600000000010
2011-01-01	11.0814000000000000
2012-01-01	12.8166000000000000
2013-01-01	18.6746000000000000
2014-01-01	17.2065000000000000
2015-01-01	17.0174000000000000