Year	Percent
1972-01-01	10.941400000000000
1973-01-01	11.217400000000000
1974-01-01	10.322700000000000
1975-01-01	10.398000000000000
1976-01-01	11.092300000000000
1977-01-01	13.241800000000000
1978-01-01	15.663300000000000
1979-01-01	12.251700000000000
1980-01-01	9.179440000000000
1981-01-01	10.590100000000000
1982-01-01	13.859900000000000
1983-01-01	17.137800000000000
1984-01-01	18.381100000000000
1985-01-01	19.251800000000000
1986-01-01	23.271500000000000
1987-01-01	21.758600000000000
1988-01-01	23.832300000000000
1989-01-01	23.310300000000000
1990-01-01	20.476800000000000
1991-01-01	22.678600000000000
1992-01-01	21.590300000000000
1993-01-01	22.169800000000000
1994-01-01	22.558900000000000
1995-01-01	22.935400000000000
1996-01-01	22.799800000000000
1997-01-01	26.230800000000000
1998-01-01	34.179300000000000
1999-01-01	32.364000000000004
2000-01-01	28.360900000000000
2001-01-01	29.893300000000000
2002-01-01	31.026700000000000
2003-01-01	30.045600000000000
2004-01-01	26.936900000000000
2005-01-01	24.169400000000000
2006-01-01	24.927300000000000
2007-01-01	29.115000000000000
2008-01-01	26.906100000000000
2009-01-01	37.727500000000000
2010-01-01	33.703700000000000
2011-01-01	32.375200000000000
2012-01-01	32.024900000000000
2013-01-01	34.017200000000000
2014-01-01	36.658500000000000
2015-01-01	47.926200000000000
2016-01-01	54.868200000000000