Year	% of total primary
1971	53.6066703796387
1972	48.2820205688477
1973	47.1052513122559
1974	46.5041618347168
1975	44.6083488464355
1976	42.8734512329102
1981	36.2904014587402
1982	35.2682113647461
1983	35.0304298400879
1984	34.7407608032227
1985	34.0793190002441
1986	33.8212394714355
1987	32.7222785949707
1988	32.2920303344727
1990	27.1569499969482
1991	25.2268390655518
1992	24.8607902526855
1994	24.4129009246826
1995	24.4909896850586
1997	24.5162601470947
1998	27.0520095825195
1999	27.673059463501
2000	27.2575492858887
2001	26.3513698577881
2002	24.8742408752441
2003	23.4565505981445
2006	22.5413093566895
2007	22.123649597168
2008	22.8498001098633
2009	22.8428592681885
2010	22.5359802246094
2011	20.9214191436768
2012	22.6998500823975
2014	22.5431499481201
2015	24.2104091644287
2016	23.8583297729492
2017	22.5248699188232
2019	24.034309387207
2021	24.7962608337402
2022	25.8242702484131