One way of meeting the required resources is by tapping on the internal means i.e. by raising the proportion of expenditure on health as a proportion of GDP. While the high-income countries are spending more than 5 per cent of their GDP on health, some developing countries including India, spend less than 1 per cent. Further, due to higher population in developing countries,this translates to very low per capita spending; in purchasing power parity terms, about $38 in low HDI countries as against $194 in medium HDI countries and $1061 in high HDI countries. The WHO's Commission on Macroeconomics and Health has recommended that donor assistance for health systems in low-income countries should be substantially increased to improve the spending on health. More importantly, the commission notes that if properly invested in high-priority areas like infectious diseases, nutritional deficiencies and maternal complications, significant economic benefits (estimated at $360 billion a year at global level) can be gained.