Year	Percent
1980-01-01	3.202340000000000
1981-01-01	2.907110000000000
1982-01-01	3.531050000000000
1983-01-01	4.444250000000000
1984-01-01	5.087880000000000
1985-01-01	8.982200000000000
1986-01-01	13.655500000000000
1987-01-01	20.505600000000000
1988-01-01	18.659000000000002
1989-01-01	18.650700000000000
1990-01-01	19.898700000000000
1991-01-01	20.344600000000000
1992-01-01	19.540500000000000
1993-01-01	18.898100000000000
1994-01-01	18.680999999999997
1995-01-01	19.177100000000000
1996-01-01	19.169100000000000
1997-01-01	17.830400000000000
1998-01-01	20.824600000000000
1999-01-01	21.658000000000000
2000-01-01	25.210100000000000
2001-01-01	27.698100000000000
2002-01-01	29.554000000000002
2003-01-01	32.654600000000000
2004-01-01	36.583500000000000
2005-01-01	36.867200000000000
2006-01-01	47.960600000000000
2007-01-01	47.621600000000000
2008-01-01	42.674600000000000
2009-01-01	52.221700000000000
2010-01-01	44.161900000000000
2011-01-01	37.175100000000000
2012-01-01	38.565600000000000
2013-01-01	41.761900000000000
2014-01-01	42.475500000000000
2015-01-01	49.447500000000000
2016-01-01	48.725500000000000