Year	% of total primary
1971	5.09932994842529
1972	6.40258979797363
1973	6.20280981063843
1974	7.16773986816406
1981	8.86874961853027
1982	9.26406955718994
1983	7.88179016113281
1984	10.79421043396
1985	10.5412998199463
1986	11.1529703140259
1987	10.7150201797485
1988	11.434700012207
1989	13.3113899230957
1991	13.2018003463745
1992	14.2741498947144
1993	15.9917602539062
1994	17.1727199554443
1995	17.9056797027588
1996	17.2489891052246
1997	17.0824394226074
1998	17.3539695739746
1999	18.775390625
2000	19.0825996398926
2001	19.7148895263672
2002	21.1184692382812
2003	21.7873401641846
2004	22.5576705932617
2005	23.6701507568359
2006	24.7355709075928
2011	32.4566307067871
2012	32.8535194396973
2013	33.8548889160156
2014	34.5933799743652
2015	35.5372886657715
2016	36.1876983642578
2017	36.5004005432129
2018	36.9114303588867
2019	37.1709289550781
2022	38.0124015808105