Year	% of total primary
1971	24.422420501709
1972	25.9570198059082
1973	25.7110691070557
1974	20.6003303527832
1976	21.9179096221924
1981	12.7400903701782
1982	12.7470903396606
1983	10.7867803573608
1984	12.2198400497437
1985	13.197380065918
1988	15.1022901535034
1989	15.450719833374
1990	16.6840801239014
1991	17.7505702972412
1992	21.7510204315186
1993	21.6071491241455
1994	21.1736392974854
1995	22.35080909729
1996	20.5809192657471
1998	22.4714698791504
1999	21.8656597137451
2000	22.6183605194092
2001	21.6201992034912
2002	21.6957302093506
2003	20.3760204315186
2004	19.3359794616699
2005	18.946439743042
2006	19.3441791534424
2007	19.0971202850342
2008	18.8357105255127
2009	17.9896297454834
2010	17.6949501037598
2011	17.7868900299072
2012	18.1127490997314
2013	19.1146392822266
2014	18.8489398956299
2015	18.5764999389648
2016	18.6544609069824
2018	19.6834602355957
2019	20.9351806640625