Year	Percent
1972-01-01	2.232160000000000
1973-01-01	4.473669999999999
1974-01-01	9.958639999999999
1975-01-01	11.621300000000000
1976-01-01	11.650000000000000
1977-01-01	14.178600000000000
1978-01-01	18.017600000000000
1979-01-01	15.250800000000000
1980-01-01	11.544600000000000
1981-01-01	11.588300000000000
1982-01-01	12.722600000000000
1983-01-01	14.424800000000000
1984-01-01	16.017200000000000
1985-01-01	17.290700000000000
1986-01-01	21.469000000000000
1987-01-01	20.542400000000000
1988-01-01	22.535600000000000
1989-01-01	22.043700000000000
1990-01-01	19.474000000000000
1991-01-01	21.338800000000000
1992-01-01	20.519800000000000
1993-01-01	22.044400000000000
1994-01-01	23.305900000000000
1995-01-01	24.352400000000000
1996-01-01	24.875300000000000
1997-01-01	30.673400000000000
1998-01-01	43.980300000000000
1999-01-01	44.589700000000000
2000-01-01	37.459800000000000
2001-01-01	38.802500000000000
2002-01-01	38.689500000000000
2003-01-01	36.478600000000000
2004-01-01	33.085800000000000
2005-01-01	28.843800000000000
2006-01-01	28.055700000000000
2007-01-01	31.052600000000000
2008-01-01	30.069500000000000
2009-01-01	45.010600000000000
2010-01-01	40.337100000000000
2011-01-01	38.866500000000000
2012-01-01	39.176600000000000
2013-01-01	41.728900000000000
2014-01-01	44.424600000000000
2015-01-01	59.807700000000000
2016-01-01	72.511600000000000