Year	% of total primary
1971	15.1751699447632
1972	14.9107103347778
1973	14.9299297332764
1974	14.2017803192139
1975	13.3915996551514
1976	13.5497903823853
1977	13.5887002944946
1978	13.5113096237183
1979	13.4156999588013
1980	13.362509727478
1981	13.4179801940918
1982	13.45458984375
1983	13.4680995941162
1984	13.5199003219604
1985	13.4854698181152
1986	13.3761100769043
1987	13.2303600311279
1988	13.2800903320312
1989	13.2616300582886
1990	13.3604097366333
1991	13.3695602416992
1992	13.5112495422363
1993	13.6772899627686
1994	13.8169498443604
1995	13.9861297607422
1996	14.1249504089355
1997	14.3389101028442
1998	14.4052400588989
1999	14.5157403945923
2000	14.6211996078491
2001	14.7938499450684
2002	14.3739500045776
2003	15.2677698135376
2004	16.2513103485107
2005	17.211389541626
2006	17.9323101043701
2007	18.7203598022461
2008	19.4518299102783
2009	20.3869895935059
2010	21.169340133667
2011	22.349250793457
2012	23.0596294403076
2013	23.4826793670654
2014	23.9551200866699
2015	23.8073997497559
2016	23.2451992034912
2017	23.9570407867432
2018	26.7984504699707
2019	26.7115898132324
2020	27.2680397033691
2021	27.2675399780273