Year	Percent
1973-01-01	7.986160000000001
1974-01-01	8.801540000000000
1975-01-01	9.542589999999999
1976-01-01	9.902810000000000
1977-01-01	12.401500000000000
1978-01-01	16.059900000000000
1979-01-01	17.059100000000000
1980-01-01	19.779100000000000
1981-01-01	23.415700000000000
1982-01-01	26.598100000000000
1983-01-01	23.211900000000000
1984-01-01	16.729400000000000
1985-01-01	15.080200000000000
1986-01-01	16.026400000000000
1987-01-01	17.177100000000000
1988-01-01	17.621500000000000
1989-01-01	16.184600000000000
1990-01-01	14.667100000000000
1991-01-01	15.950600000000000
1992-01-01	16.136600000000000
1993-01-01	16.177800000000000
1994-01-01	22.786100000000000
1995-01-01	15.651000000000000
1996-01-01	18.007900000000000
1997-01-01	19.105000000000000
1998-01-01	20.372100000000000
1999-01-01	25.536300000000000
2000-01-01	29.249200000000000
2001-01-01	30.002500000000000
2002-01-01	31.248700000000000
2003-01-01	30.898600000000000
2004-01-01	33.103900000000000
2005-01-01	32.192000000000000
2006-01-01	38.113500000000000
2007-01-01	41.991500000000000
2008-01-01	40.839800000000000
2009-01-01	43.824200000000000
2010-01-01	46.135300000000000
2011-01-01	43.286000000000000
2012-01-01	42.806500000000000
2013-01-01	44.405000000000000
2014-01-01	43.606000000000000
2015-01-01	44.134100000000000
2016-01-01	46.963300000000000