Year	Percent
1986-01-01	3.71875927616865
1987-01-01	4.11978946046856
1988-01-01	5.92979706055667
1989-01-01	7.52955175330778
1990-01-01	8.49354168923632
1991-01-01	11.41396561608760
1992-01-01	11.55793189008760
1993-01-01	10.59481300994310
1994-01-01	8.90050559190656
1995-01-01	6.52686716856974
1996-01-01	6.43169896719334
1997-01-01	6.94908441946702
1998-01-01	7.93625272281954
1999-01-01	7.42311007725290
2000-01-01	6.36711574227112
2001-01-01	5.59273278467734
2002-01-01	5.22857181337899
2003-01-01	4.52830882056890
2004-01-01	3.63149144575163
2005-01-01	3.59671771819059
2006-01-01	3.62095848687575
2007-01-01	3.44490967963649
2008-01-01	4.04281419308756
2009-01-01	6.03202931734185
2010-01-01	6.09875331569651
2011-01-01	6.01822157461692
2012-01-01	6.40462520075072
2013-01-01	5.42446002152547
2014-01-01	4.93622036899576
2015-01-01	5.14032192754480
2016-01-01	5.02225896358274
2017-01-01	4.49841430943177