Year	% of total primary
1971	0.48581999540329
1972	0.46136000752449
1973	0.452769994735718
1974	0.453060001134872
1982	0.378549993038177
1983	0.35139998793602
1984	0.291139990091324
1985	0.311199992895126
1986	0.373180001974106
1987	0.466829985380173
1988	0.537320017814636
1989	0.599969983100891
1990	0.641480028629303
1991	0.647520005702972
1992	0.64521998167038
1993	0.649479985237122
1994	0.691269993782043
1995	0.750819981098175
2012	2.66142010688782
2013	2.99219989776611
2014	3.30632996559143
2015	3.74063992500305
2016	4.32851982116699
2017	4.28589010238647
2018	4.57901000976562
2019	4.97712993621826
2020	5.18978977203369
2021	5.05427980422974