Year	% of total primary
1970	4.79465007781982
1998	10.9759902954102
2000	11.1735897064209
2001	10.7887601852417
2002	10.3709096908569
2003	9.67553997039795
2005	9.75032043457031
2006	10.0943899154663
2007	10.2938404083252
2008	10.6529998779297
2009	10.4372100830078
2010	9.66462993621826
2011	10.1059103012085
2012	10.3815002441406
2013	10.7901296615601
2014	12.5263299942017
2015	12.5052299499512
2016	12.9881000518799
2017	12.7782402038574
2018	13.2875604629517
2019	13.8438396453857
2020	13.9207601547241
2021	12.3213195800781