Year	% of total
1992	19.546306712655877
1993	21.46874714260594
1994	19.038152468041428
1995	19.889460106106316
1996	19.18094026776519
1997	19.476630777044182
1998	16.666423107359538
1999	17.183279972159387
2000	16.184942887665375
2001	15.867229102167185
2002	15.283309673817689
2003	17.3013219508072
2004	15.715282879024953
2005	12.83977005487327
2006	12.041883047650291
2007	11.250424165610477
2008	10.487265700483091
2009	10.671367611052816
2010	8.416507016971279
2011	7.768620441458733
2012	7.7498283763141345
2013	7.182950587819323
2014	7.25677070486671
2015	7.328221215404314
2016	6.111097345132743