Year	% of internal resources
1980	24.886363636363637
1981	25.615530303030305
1982	26.34469696969697
1983	27.073863636363637
1984	27.8030303030303
1985	28.532196969696965
1986	29.261363636363637
1987	29.9905303030303
1988	30.71969696969697
1989	31.44886363636364
1990	32.178030303030305
1991	32.90719696969697
1992	33.63636363636363
1993	34.3655303030303
1994	35.09469696969697
1995	35.82386363636363
1996	36.5530303030303
1997	37.28219696969697
1998	38.01136363636364
1999	38.740530303030305
2000	39.46969696969697
2001	39.666666666666664
2002	39.86363636363636
2003	40.06060606060606
2004	40.25757575757575
2005	40.45454545454545
2006	40.45454545454545
2007	40.45454545454545
2008	40.45454545454545
2009	40.45454545454545
2010	40.45454545454545
2011	40.45454545454545
2012	40.45454545454545
2013	40.45454545454545
2014	40.45454545454545
2015	40.45454545454545
2016	40.45454545454545
2017	40.45454545454545
2018	40.45454545454545
2019	40.45454545454545
2020	40.45454545454545