Year	% of total
1990	4.317718768516872
1991	2.8388614299874178
1992	5.817286867848608
1993	5.392736287180286
1994	4.817937526395832
1995	3.603955769519649
1996	3.4662115974652723
1997	3.8320852754239003
1998	2.707284449486889
1999	3.1035987475753477
2000	4.304429467753641
2001	3.9880655300060806
2002	3.9941550193139066
2003	3.8219436575764707
2004	3.7594906992881247
2005	3.592045952020387
2006	3.3517795441430778
2007	3.742834183677585
2008	4.2315999147148675
2009	4.413888525900911
2010	5.002070461864537
2011	5.926809423706497
2012	6.362821876851637
2013	6.667799642587427
2014	7.848833511456589
2015	10.66760156638583
2016	12.402277094699304