Year	Percent
1977-01-01	0.33769299999999997
1978-01-01	0.28087000000000000
1979-01-01	0.26645000000000000
1980-01-01	0.40628100000000000
1981-01-01	0.48765900000000000
1982-01-01	0.36030800000000000
1983-01-01	0.28965200000000000
1984-01-01	0.30052800000000000
1985-01-01	0.51176000000000000
1986-01-01	2.60260000000000000
1987-01-01	16.23050000000000000
1988-01-01	19.04490000000000000
1989-01-01	14.15530000000000000
1990-01-01	13.77760000000000000
1991-01-01	10.60400000000000100
1992-01-01	9.33828000000000100
1993-01-01	10.86110000000000000
1994-01-01	14.24980000000000000
1995-01-01	15.49230000000000000
1996-01-01	17.40780000000000000
1997-01-01	25.82780000000000000
1998-01-01	40.54900000000000000
1999-01-01	50.25800000000000000
2000-01-01	50.41560000000000000
2001-01-01	43.54550000000000000
2002-01-01	34.17610000000000000
2003-01-01	33.24840000000000000
2004-01-01	35.50160000000000000
2005-01-01	34.73670000000000000
2006-01-01	41.20120000000000000
2007-01-01	51.24390000000000000
2008-01-01	40.62100000000000000
2009-01-01	33.49750000000000000
2010-01-01	36.88940000000000000
2011-01-01	30.43360000000000000
2012-01-01	28.46500000000000000
2013-01-01	32.42140000000000000
2014-01-01	29.68340000000000000
2015-01-01	27.12760000000000000
2016-01-01	28.51210000000000000
2017-01-01	30.82290000000000000