Year	% of total
1990	13.068904144419019
1991	12.447525760081414
1992	7.810573645659584
1993	8.495590674932332
1994	5.218919538473294
1995	4.746237311865594
1996	5.25780405620192
1997	6.293314665733287
1998	7.041348855881171
1999	3.8273788468341
2000	4.293081508271382
2001	4.529157825418892
2002	4.764301291729576
2003	3.6302688823906997
2004	3.460801796446734
2005	10.100060439191457
2006	10.321558906562005
2007	10.755225893459205
2008	11.324115701077275
2009	3.4828115131282145
2010	4.991735537190083
2011	4.189207019395699
2012	4.799578059071729
2013	5.609877953036899
2014	7.363436727971452
2015	13.215656178050653