Year	% of total primary
1981	2.18121004104614
1982	1.83173000812531
1983	1.76470994949341
1984	2.05574011802673
1985	2.19652009010315
1986	2.24295997619629
1987	2.32634997367859
1988	2.40072989463806
1989	2.40052008628845
1990	2.41459989547729
1991	2.38844990730286
1992	2.26161003112793
1993	3.27611994743347
1994	3.20163989067078
1995	3.20784997940063
1996	3.15528988838196
1998	3.20618009567261
1999	3.29828000068665
2000	3.31815004348755
2001	3.35959005355835
2002	3.59343004226685
2003	3.71187996864319
2004	3.76701998710632
2005	3.80640006065369
2006	3.93787002563477
2007	4.06614017486572
2008	4.19247007369995
2009	4.47346019744873
2010	4.57556009292603
2011	4.85601997375488
2012	4.80964994430542
2013	5.60669994354248
2014	5.63504981994629
2015	5.59647989273071
2016	5.6040301322937
2017	5.475830078125
2018	5.50902986526489
2019	5.49697017669678
2020	5.49517011642456
2021	5.48101997375488
2022	5.53121995925903