Year	Percent
1972-01-01	0.62363800000000000
1973-01-01	0.49588999999999994
1974-01-01	0.48617200000000005
1975-01-01	0.44984700000000005
1976-01-01	2.60855999999999980
1977-01-01	2.92140000000000000
1978-01-01	3.65099000000000000
1979-01-01	3.45426999999999970
1980-01-01	3.22337000000000000
1981-01-01	2.97926000000000000
1982-01-01	2.85405000000000000
1983-01-01	3.11332000000000000
1984-01-01	2.99282000000000000
1985-01-01	3.04545000000000000
1986-01-01	2.78891000000000000
1987-01-01	2.59369000000000000
1988-01-01	1.72890000000000000
1989-01-01	1.15091000000000000
1990-01-01	2.82996000000000000
1991-01-01	2.53206000000000000
1992-01-01	8.09983999999999900
1993-01-01	10.06100000000000000
1994-01-01	10.36760000000000000
1995-01-01	10.09440000000000000
1996-01-01	13.47530000000000000
1997-01-01	17.14020000000000000
1998-01-01	20.28060000000000000
1999-01-01	21.73500000000000000
2000-01-01	23.07150000000000000
2001-01-01	24.47870000000000000
2002-01-01	27.80810000000000000
2003-01-01	31.79430000000000000
2004-01-01	30.74380000000000000
2005-01-01	28.65390000000000000
2006-01-01	26.23670000000000000
2007-01-01	21.73740000000000000
2008-01-01	18.28180000000000000
2009-01-01	21.49050000000000000
2010-01-01	20.00590000000000000
2011-01-01	18.58810000000000000
2012-01-01	18.06490000000000000
2013-01-01	16.99520000000000000
2014-01-01	16.17480000000000000
2015-01-01	16.80890000000000000
2016-01-01	15.95900000000000100