Year	Percent
1973-01-01	19.096400000000000
1974-01-01	17.969600000000000
1975-01-01	17.208000000000000
1976-01-01	17.708900000000000
1977-01-01	18.103800000000000
1978-01-01	18.322200000000000
1979-01-01	17.839800000000000
1980-01-01	18.039600000000000
1981-01-01	17.828800000000000
1982-01-01	18.540600000000000
1983-01-01	18.562500000000000
1984-01-01	15.703500000000000
1985-01-01	13.555900000000000
1986-01-01	13.167400000000000
1987-01-01	11.769000000000000
1988-01-01	12.495800000000000
1989-01-01	13.649400000000000
1990-01-01	14.200300000000000
1991-01-01	14.054100000000000
1992-01-01	17.433800000000000
1993-01-01	20.067200000000000
1994-01-01	23.483500000000000
1995-01-01	23.792500000000000
1996-01-01	24.196200000000000
1997-01-01	26.547400000000000
1998-01-01	25.471999999999998
1999-01-01	24.463500000000000
2000-01-01	24.624500000000000
2001-01-01	23.934500000000000
2002-01-01	22.198500000000000
2003-01-01	18.212200000000000
2004-01-01	15.148400000000000
2005-01-01	15.080500000000000
2006-01-01	14.947600000000000
2007-01-01	16.039200000000000
2008-01-01	19.540800000000000
2009-01-01	27.395000000000000
2010-01-01	31.383900000000000
2011-01-01	36.855300000000000
2012-01-01	41.635800000000000
2013-01-01	42.704500000000000
2014-01-01	47.769600000000000
2015-01-01	55.090100000000000
2016-01-01	55.657800000000000