Year	Percent
1986-01-01	3.51134969451624
1987-01-01	3.10987649187480
1988-01-01	4.05110459739971
1989-01-01	5.07063399465447
1990-01-01	5.32817965733576
1991-01-01	7.32011783634527
1992-01-01	7.52217125442156
1993-01-01	6.78834273838636
1994-01-01	5.84111415393760
1995-01-01	4.89127091467814
1996-01-01	4.89399679035383
1997-01-01	5.19328457587112
1998-01-01	6.09995570942861
1999-01-01	5.32821576906393
2000-01-01	4.59612647359589
2001-01-01	4.02553613538283
2002-01-01	4.10409660107900
2003-01-01	3.92174377523974
2004-01-01	3.29663135942158
2005-01-01	2.88264791937055
2006-01-01	2.84493680609646
2007-01-01	2.59708649004388
2008-01-01	2.80632907252950
2009-01-01	3.75332500598472
2010-01-01	4.44320602342088
2011-01-01	4.54068782000720
2012-01-01	4.86485382713868
2013-01-01	4.73078131961728
2014-01-01	4.52391563397970
2015-01-01	4.39529015624865
2016-01-01	4.01218541405568
2017-01-01	3.76796440556146