Year	% of total primary
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	1.38717997074127
1994	2.22156000137329
1995	2.61946988105774
1996	3.21663999557495
1997	4.04174995422363
1998	4.20814990997314
1999	4.67611980438232
2000	5.12231016159058
2001	5.13895988464355
2002	5.15669012069702
2003	5.31881999969482
2004	5.82835006713867
2005	6.40024995803833
2006	6.80712985992432
2007	7.34050989151001
2008	7.8686900138855
2009	8.24934005737305
2010	8.70405006408691
2011	9.19171047210693
2012	10.8992395401001
2013	13.9903402328491
2014	14.8580198287964
2015	15.375340461731
2016	15.9702701568604
2017	16.7337608337402
2018	17.5060291290283
2019	18.0580902099609
2020	18.4683094024658
2021	19.1174392700195