Year	% of total primary
1970	12.9202499389648
1971	13.5378398895264
1972	13.7296104431152
1973	13.4172697067261
1982	14.7511796951294
1985	13.7187204360962
1986	15.122989654541
1987	13.6458902359009
1988	14.6204500198364
1989	15.045280456543
1990	14.9772100448608
1991	14.0585803985596
1992	13.3903903961182
1993	13.2691497802734
1994	13.4926900863647
1995	13.9205503463745
1996	13.8545598983765
1997	14.7878198623657
1998	14.5268697738647
2001	14.9743204116821
2002	15.6326103210449
2003	16.456169128418
2004	16.4403305053711
2005	16.613260269165
2006	16.721549987793
2007	17.5040397644043
2008	18.1423892974854
2009	18.2782001495361
2010	18.2941303253174
2011	18.9258899688721
2016	20.1583003997803
2020	20.9537200927734
2021	20.2087306976318
2022	20.4937896728516