Year	% of total primary
1971	6.1279501914978
1972	6.74221992492676
1973	6.4752402305603
1974	6.22888994216919
1975	5.40319013595581
1976	4.57441997528076
1977	4.50992012023926
1981	2.99491000175476
1982	3.07896995544434
1983	3.05543994903564
1984	2.56236004829407
1985	2.95083999633789
1986	2.69335007667542
1987	3.08539009094238
1989	2.54402995109558
1990	2.76504993438721
1991	2.78169989585876
1992	2.7702100276947
1995	3.22723007202148
1996	3.31349992752075
1997	3.97530007362366
1999	3.96276998519897
2000	4.29881000518799
2001	4.43503999710083
2002	3.75643992424011
2003	3.71784996986389
2004	3.85159993171692
2005	4.14028978347778
2006	3.98961997032166
2007	3.8543701171875
2008	4.03090000152588
2009	3.9279899597168
2010	3.83126997947693
2011	3.75093007087708
2012	3.49405002593994
2013	3.46060991287231
2014	3.41388988494873
2015	3.30976009368896
2016	3.4193000793457
2017	3.61044001579285
2019	3.55488991737366
2021	3.81533002853394
2022	4.0321102142334