Year	% of internal resources
1980	39.603960396039604
1981	44.35643564356435
1982	49.1089108910891
1983	53.86138613861385
1984	58.61386138613861
1985	53.26732673267326
1986	52.554455445544555
1987	51.841584158415834
1988	51.12871287128712
1989	50.415841584158414
1990	49.7029702970297
1991	48.99009900990099
1992	48.27722772277227
1993	47.56435643564356
1994	46.85148514851485
1995	46.13861386138614
1996	49.165487920792074
1997	52.19236217821782
1998	55.21923623762376
1999	58.246110297029695
2000	61.272984356435636
2001	64.29985861386139
2002	67.32673267326733
2003	68.43564356435643
2004	68.51485148514851
2005	70.65346534653466
2006	71.76237623762376
2007	72.87128712871286
2008	70.89108910891089
2009	62.77227722772276
2010	80.99009900990099
2011	75.44554455445545
2012	79.4059405940594
2013	91.2871287128713
2014	89.1089108910891
2015	82.77227722772275
2016	82.97029702970296
2017	91.08910891089108
2018	84.62300297029704
2019	80.999060990099
2020	81.85993960396038