Year	% of internal resources
1980	0.5235602094240838
1981	0.5304303010471203
1982	0.5373036649214661
1983	0.5441704842931937
1984	0.5510405759162303
1985	0.557910667539267
1986	0.5647807591623036
1987	0.5716508507853404
1988	0.578520942408377
1989	0.5853910340314136
1990	0.5922611256544502
1991	0.5991312172774869
1992	0.6060013089005236
1993	0.6128714005235603
1994	0.6197414921465969
1995	0.6266115837696334
1996	0.6334816753926702
1997	0.6272338568848168
1998	0.6209860384031414
1999	0.614738219895288
2000	0.6299513836910995
2001	0.6725467464397905
2002	0.6685976065706806
2003	0.6750411368848168
2004	0.7354113687434555
2005	0.7170643231151833
2006	0.7693717277486911
2007	0.7921465968586388
2008	0.768128272251309
2009	0.744109947643979
2010	0.7344502617801048
2011	0.7247905759162303
2012	0.715130890052356
2013	0.720890052356021
2014	0.727434554973822
2015	0.7103403141361256
2016	0.6932460732984294
2017	0.7044764397905758
2018	0.7044764397905758
2019	0.7044764397905758
2020	0.7044764397905758