Year	% of internal resources
1975	66.12903225806451
1976	68.59237536656892
1977	71.0557184750733
1978	73.51906158357771
1979	75.9824046920821
1980	78.4457478005865
1981	80.90909090909089
1982	83.3724340175953
1983	85.83577712609971
1984	88.29912023460409
1985	90.76246334310851
1986	98.47507331378299
1987	106.18768328445746
1988	113.90029325513196
1989	121.61290322580645
1990	122.43401759530789
1991	129.84918307917889
1992	137.2643485483871
1993	133.8474025953079
1994	130.62840385630497
1995	127.40940511730203
1996	124.19040636363636
1997	120.97140762463343
1998	117.77126099706746
1999	113.54472140762464
2000	109.31818181818183
2001	102.36175115835775
2002	108.30854629032257
2003	108.97674906158356
2004	117.70946794721407
2005	127.00879765395894
2006	134.45747800586508
2007	136.65689149560117
2008	136.07038123167155
2009	126.53958944281524
2010	130.9384164222874
2011	116.71554252199414
2012	124.48680351906157
2013	132.1114369501466
2014	142.19941348973606
2015	127.30205278592375
2016	132.49266862170086
2017	132.9765395894428
2018	135.3372434017595
2019	138.09970674486803
2020	138.09970674486803