Year	% of total primary
1970	5.15890979766846
1971	5.941969871521
1972	6.38362979888916
1973	6.01710987091064
1974	6.02442979812622
1975	5.425950050354
1980	4.70584011077881
1981	4.37320995330811
1983	5.79999017715454
1984	3.15055990219116
1985	5.64291000366211
1987	5.22820997238159
1988	4.98676013946533
1989	6.0968599319458
1990	5.16902017593384
1992	3.94285988807678
1994	6.14423990249634
1995	3.96979999542236
1996	3.81069993972778
1997	4.49252986907959
1998	4.26212978363037
1999	4.6571102142334
2000	4.88555002212524
2001	4.67686986923218
2004	5.12698984146118
2006	5.32932996749878
2007	5.02873992919922
2008	5.24182987213135
2009	5.81633996963501
2012	6.10577011108398
2013	6.80251979827881
2014	7.03609991073608
2015	7.39021015167236
2021	6.9380898475647