Year	% of total primary
1971	0
1972	0.369370013475418
1973	0.373169988393784
1974	0.327549993991852
1975	0.31402000784874
1976	0.379720002412796
1981	0.586790025234222
1982	0.619090020656586
1983	0.644559979438782
1984	0.685959994792938
1985	0.703090012073517
1986	0.73869001865387
1987	0.747510015964508
1988	0.790520012378693
1989	0.808340013027191
1990	0.881529986858368
1991	0.913969993591309
1992	0.976199984550476
1993	1.12813997268677
1994	1.58880996704102
1995	1.99000000953674
1996	2.18782997131348
1997	2.51045989990234
1999	2.97904992103577
2000	3.35978007316589
2001	3.9334499835968
2002	4.61188983917236
2003	5.09635019302368
2004	6.11820983886719
2005	6.57761001586914
2006	7.150710105896
2007	7.71460008621216
2008	8.38665962219238
2009	8.84226989746094
2010	9.49038028717041
2011	10.1470003128052
2012	10.8888502120972
2013	9.69005012512207
2014	9.18704986572266
2015	10.1003503799438
2016	10.4687995910645
2017	10.4695701599121
2018	10.5687198638916
2019	10.9809303283691
2020	11.2487297058105
2021	11.6973695755005
2022	12.1079196929932