Year	% of total primary
1970	35.7137718200684
1971	35.8650703430176
1972	35.8451614379883
1973	35.4233016967773
1982	24.0236396789551
1983	24.4353504180908
1984	23.8002490997314
1985	23.8096103668213
1986	23.6362590789795
1987	23.8640193939209
1988	23.4662704467773
1989	23.9096603393555
1990	24.0105895996094
1991	24.1253890991211
1992	24.4167003631592
1993	24.9661598205566
1994	26.2388591766357
1995	26.6029205322266
2007	5.33142995834351
2008	6.81738996505737
2009	7.5858302116394
2016	3.94145011901855
2017	3.87720990180969
2018	3.96012997627258
2019	4.08942985534668
2020	4.19053983688354
2021	4.4074501991272