Year	Percent
1987-01-01	3.93132510096869
1988-01-01	3.59813553618518
1989-01-01	2.99767718510894
1990-01-01	2.75193941946244
1991-01-01	2.63036022023630
1992-01-01	2.83240210402476
1993-01-01	3.42952947059277
1994-01-01	3.70684093468154
1995-01-01	6.22835270513873
1996-01-01	5.44476457173891
1997-01-01	3.72715443424819
1998-01-01	3.15727088455679
1999-01-01	2.50086484504102
2000-01-01	2.50727448318701
2001-01-01	2.76621149600000
2002-01-01	2.97794452758333
2003-01-01	3.39984692833333
2004-01-01	3.91807542191667
2005-01-01	3.55914631753044
2006-01-01	3.56451748002556
2007-01-01	3.64540821019204
2008-01-01	3.90419724918359
2009-01-01	5.37592983677716
2010-01-01	5.32946230725116
2011-01-01	5.19548996170682
2012-01-01	4.92332187005275
2013-01-01	4.94333948424774
2014-01-01	4.83135373256103
2015-01-01	4.33603494077710
2016-01-01	3.88517953642185
2017-01-01	3.43800067234966