Year	% of total primary
1993	1.76383996009827
1994	1.78934001922607
1995	1.82753002643585
1996	1.86211001873016
1997	1.88716995716095
1999	2.07295989990234
2000	2.21487998962402
2001	2.38624000549316
2002	2.56736993789673
2003	2.71947002410889
2004	2.86093997955322
2005	3.11952996253967
2006	3.32308006286621
2007	3.33788990974426
2008	3.61188006401062
2009	3.87057995796204
2010	4.10953998565674
2011	4.34100008010864
2012	4.49279022216797
2013	4.64816999435425
2014	4.78770017623901
2015	4.87717008590698
2016	4.96533012390137
2017	4.98721981048584
2018	5.04905986785889
2019	5.16484022140503
2020	5.24229001998901
2021	5.26700019836426