Year	% of total primary
1971	92.4808578491211
1972	92.7545928955078
1973	93.8811798095703
1974	94.6051025390625
1975	95.3517837524414
1976	95.8677978515625
1981	94.1602172851562
1982	94.0320892333984
1983	93.6929168701172
1984	93.4171295166016
1985	93.2300186157227
1986	10.21399974823
1987	9.84185981750488
1988	9.74267959594727
1989	9.68251037597656
1990	9.59097957611084
1991	9.49956035614014
1992	9.58545017242432
1993	9.72978019714355
1994	9.91689968109131
1995	10.39976978302
1996	10.3301601409912
2002	10.4295301437378
2003	10.4294700622559
2004	10.6857595443726
2005	11.1729297637939
2006	12.1544504165649
2007	12.8038301467896
2008	13.6483602523804
2009	14.8227701187134
2010	15.7601900100708
2011	16.6888408660889
2012	17.5676307678223
2013	18.3874206542969
2014	18.8508491516113
2015	19.0018405914307
2016	18.9448299407959
2017	18.8847808837891
2018	18.7738609313965
2019	18.7688293457031
2020	19.1425304412842
2021	19.2733306884766
2022	19.6566295623779