Year	Percent
1986-01-01	2.97143516445952
1987-01-01	2.95643310726178
1988-01-01	4.23063802352504
1989-01-01	5.43220556300130
1990-01-01	6.19390979404881
1991-01-01	8.44101296484189
1992-01-01	8.59181378218258
1993-01-01	7.96274745044662
1994-01-01	6.78535726405312
1995-01-01	5.22961109935225
1996-01-01	5.06966675071939
1997-01-01	5.48303871321373
1998-01-01	6.36485090821232
1999-01-01	5.68016205341119
2000-01-01	4.65935466059367
2001-01-01	4.22970476631668
2002-01-01	4.11564989249245
2003-01-01	3.62112244355969
2004-01-01	2.98899847148910
2005-01-01	2.77599471746272
2006-01-01	2.72214385105063
2007-01-01	2.53258832912406
2008-01-01	2.85761869779917
2009-01-01	4.22092371271381
2010-01-01	4.62620396513669
2011-01-01	4.57998091368372
2012-01-01	4.93325902879818
2013-01-01	4.41839136231892
2014-01-01	4.20498519945137
2015-01-01	4.09719251773792
2016-01-01	3.89712851314781
2017-01-01	3.51756098396218