Year % of internal resources 1970 3.08411214953271 1971 3.1308411214953273 1972 3.177570093457944 1973 3.224299065420561 1974 3.2710280373831773 1975 3.3177570093457938 1976 3.345794392523364 1977 3.3738317757009346 1978 3.4018691588785046 1979 3.429906542056075 1980 3.4579439252336446 1981 3.514018691588785 1982 3.570093457943925 1983 3.6261682242990654 1984 3.6822429906542054 1985 3.7383177570093453 1986 3.4256074766355145 1987 3.1128971962616823 1988 2.80018691588785 1989 2.4874766355140188 1990 2.174766355140187 1991 2.223177570093458 1992 2.271588785046729 1993 2.3200000000000003 1994 2.368411214953271 1995 2.416822429906542 1996 2.3564719626168222 1997 2.2961214953271027 1998 2.2357710280373833 1999 2.1754205607476638 2000 2.743511348504673 2001 3.3116021361682244 2002 3.879692923925234 2003 4.442947262990655 2004 5.006201602149533 2005 5.569455941214954 2006 6.132710280373832 2007 5.734392523364486 2008 5.33607476635514 2009 4.937757009345795 2010 4.539439252336448 2011 4.141121495327103 2012 3.742803738317757 2013 3.3444859813084107 2014 2.9461682242990657 2015 2.5478504672897193 2016 2.1495327102803734 2017 2.1495327102803734 2018 2.616822429906542 2019 2.803738317757009 2020 2.803738317757009