Year	% of total primary
1972	1.82160997390747
1982	2.69173002243042
1983	2.87083005905151
1984	2.97952008247375
1985	3.01892995834351
1986	3.21341991424561
1987	3.33228993415833
1988	3.51310992240906
1989	3.62005996704102
1990	3.61777997016907
1991	3.66948008537292
1992	3.74785995483398
1993	3.93227005004883
1994	4.13309001922607
1995	4.18709993362427
1996	4.18708992004395
1998	4.52821016311646
1999	6.47713994979858
2000	6.47768020629883
2005	5.89201021194458
2006	5.82033014297485
2007	5.82028007507324
2008	4.97788000106812
2009	6.03573989868164
2010	6.12328004837036
2011	5.82418012619019
2012	5.80994987487793
2013	5.84188985824585
2014	6.04584980010986
2015	6.23391008377075
2016	6.18410015106201
2017	6.22495985031128
2018	6.24444007873535
2019	6.36286020278931
2020	6.37664985656738
2021	6.3998498916626