Year	Percent
1977-01-01	0.2554510000000000400
1978-01-01	0.3558130000000000000
1979-01-01	0.3419000000000000000
1980-01-01	0.3325420000000000000
1981-01-01	0.2846349999999999700
1982-01-01	0.1227490000000000000
1983-01-01	0.0430940000000000000
1984-01-01	0.0359030000000000000
1985-01-01	0.0102860000000000000
1986-01-01	0.0096790000000000000
1987-01-01	0.0014119999999999998
1988-01-01	0.5827890000000000000
1989-01-01	1.0106100000000000000
1990-01-01	1.5516100000000000000
1991-01-01	1.9019599999999999000
1992-01-01	2.2086300000000000000
1993-01-01	2.1122900000000002000
1994-01-01	2.1912900000000000000
1995-01-01	2.4393700000000003000
1996-01-01	2.3949200000000000000
1997-01-01	2.2934200000000002000
1998-01-01	2.3536400000000000000
1999-01-01	2.5417000000000000000
2000-01-01	3.0909100000000000000
2001-01-01	3.3885500000000000000
2002-01-01	7.7018699999999995000
2003-01-01	9.7955500000000000000
2004-01-01	10.9638000000000000000
2005-01-01	11.2696000000000000000
2006-01-01	12.2393000000000000000
2007-01-01	12.4181000000000000000
2008-01-01	11.3955000000000000000
2009-01-01	10.6518000000000000000
2010-01-01	10.2368000000000000000
2011-01-01	9.4927600000000000000
2012-01-01	9.9837300000000000000
2013-01-01	9.9887900000000000000
2014-01-01	9.9416600000000000000
2015-01-01	10.3074000000000000000
2016-01-01	10.8812000000000000000
2017-01-01	11.1781000000000000000