Year	% of total primary
1982	3.70284008979797
1991	3.20472002029419
1994	3.235759973526
2000	4.18599987030029
2001	4.27252006530762
2002	5.01930999755859
2003	4.65939998626709
2004	3.1478099822998
2005	2.5646800994873
2007	3.79834008216858
2008	6.0777702331543
2009	6.27809000015259
2010	5.00865983963013
2011	10.5964202880859
2012	10.4337100982666
2013	10.1109600067139
2014	10.52357006073
2015	10.5672798156738
2016	10.676079750061
2017	10.763090133667
2018	11.2062397003174