Year	% of internal resources
1975	19.871794871794872
1976	20.43589743589743
1977	21
1978	21.564102564102562
1979	22.128205128205128
1980	22.69230769230769
1981	23.282051282051285
1982	23.871794871794872
1983	24.46153846153846
1984	25.051282051282048
1985	25.641025641025646
1986	26.23076923076923
1987	26.974358974358974
1988	27.641025641025642
1989	28.307692307692307
1990	28.589743589743588
1991	27.94871794871795
1992	27.307692307692307
1993	26.666666666666668
1994	25.805860807692305
1995	24.94505494871795
1996	24.08424908974359
1997	23.223443217948716
1998	22.36263735897436
1999	21.501831499999998
2000	20.64102564102564
2001	19.223443217948716
2002	21.884615384615383
2003	21.715384615384615
2004	21.546153846153842
2005	21.376923076923077
2006	21.20769230769231
2007	21.038461538461537
2008	20.576923076923077
2009	23.628205128205128
2010	25.756410256410255
2011	28.307692307692307
2012	32.73076923076923
2013	26.51282051282051
2014	27.82051282051282
2015	29.743589743589745
2016	27.94871794871795
2017	27.69230769230769
2018	26.53846153846154
2019	29.615384615384617
2020	35.256410256410255