Year	% of total primary
1970	13.4317102432251
1971	13.2348299026489
1972	10.9272298812866
1973	14.9791097640991
1974	14.7824201583862
1980	14.4781198501587
1981	14.5929203033447
1982	13.4371795654297
1983	13.5007295608521
1984	13.6921901702881
1985	13.453709602356
1986	13.6198902130127
1987	15.1823797225952
1988	15.1556997299194
1989	15.1748199462891
1990	15.2386703491211
1991	15.3495798110962
1992	17.2866096496582
1993	17.179500579834
1994	18.6906299591064
1995	18.0000095367432
1996	19.2802295684814
1998	19.557430267334
1999	19.5566902160645
2000	18.7476997375488
2001	18.8253498077393
2002	17.091329574585
2004	16.9335498809814
2005	18.6927509307861
2006	19.2509307861328
2007	19.672679901123
2008	19.8088607788086
2009	18.3137092590332
2010	18.3682193756104
2011	18.5125102996826
2012	18.6288509368896
2013	18.3064098358154
2014	18.661600112915
2015	19.8063106536865
2016	19.4931106567383
2017	19.7027606964111
2018	19.6951198577881
2019	19.9098091125488
2020	19.8428001403809
2021	18.3662891387939
2022	19.315710067749