Year	% of internal resources
1970	2.3818713450292397
1971	2.389122807017544
1972	2.396374269005848
1973	2.4036257309941518
1974	2.4108771929824564
1975	2.41812865497076
1976	2.4147368421052633
1977	2.4113450292397665
1978	2.407953216374269
1979	2.404561403508772
1980	2.4011695906432746
1981	2.2683040935672514
1982	2.135438596491228
1983	2.002573099415205
1984	1.8697076023391812
1985	1.7368421052631582
1986	1.7372807017543859
1987	1.737719298245614
1988	1.7381578947368421
1989	1.7385964912280703
1990	1.735672514619883
1991	1.7371345029239766
1992	1.7385964912280703
1993	1.69025341128655
1994	1.6419103314035086
1995	1.5935672514619883
1996	1.5894736842105264
1997	1.585380116959064
1998	1.5808966861403508
1999	1.5764132553801171
2000	1.5719298245614035
2001	1.5649122807017544
2002	1.5649122807017544
2003	1.5561403508771932
2004	1.5473684210526315
2005	1.53859649122807
2006	1.5383040935672516
2007	1.5380116959064327
2008	1.5495126705847952
2009	1.5610136452046783
2010	1.5725146198830409
2011	1.5357894736842106
2012	1.4990643274853803
2013	1.4623391812865496
2014	1.4256140350877193
2015	1.3888888888888888
2016	1.4015204678362572
2017	1.414152046783626
2018	1.426783625730994
2019	1.4394152046783624
2020	1.4520467836257311