Year	% of internal resources
1975	25.50655542312277
1976	29.463647199046484
1977	33.4207389749702
1978	37.37783075089392
1979	41.334922526817635
1980	45.29201430274135
1981	47.19904648390941
1982	49.106078665077476
1983	51.01311084624554
1984	52.92014302741359
1985	54.827175208581636
1986	58.522050059594754
1987	62.216924910607865
1988	65.91179976162097
1989	69.60667461263408
1990	73.1108462455304
1991	72.0715137067938
1992	71.0321811680572
1993	69.99284862932062
1994	68.95351609058402
1995	67.91418355184744
1996	66.85578069129917
1997	65.79737783075089
1998	64.73897497020262
1999	63.680572109654356
2000	61.97854588796186
2001	66.96066746126341
2002	67.31823599523241
2003	67.67580452920143
2004	68.03337306317044
2005	68.39094159713946
2006	68.74851013110845
2007	69.10607866507746
2008	69.46364719904649
2009	71.87127532777116
2010	74.27890345649583
2011	76.6865315852205
2012	79.11323003575684
2013	81.5399284862932
2014	83.96662693682956
2015	86.3933253873659
2016	88.82002383790226
2017	84.05244338498211
2018	90.1244338498212
2019	90.41716328963051
2020	92.10965435041716