Year	% of total
1992	26.884639546254647
1993	22.297576826196472
1994	23.770224931143527
1995	19.65102098794063
1996	16.485599066044028
1997	24.03893304944405
1998	21.452737875997542
1999	18.655959408033826
2000	19.50531914893617
2001	26.11184589255386
2002	22.34738514737362
2003	17.35031768158474
2004	22.543432964984692
2005	17.30585672082718
2006	17.68486598967871
2007	22.54377981069219
2008	15.075145898883669
2009	13.56944422681422
2010	21.193052287874046
2011	15.534671125975475
2012	13.414335169158143
2013	18.545286728563624
2014	15.757575890464356
2015	21.667668408826945
2016	19.14232535198637