Certain countries rich in natural resources have been said to suffer from the apparently paradoxical "resource curse" - showing "worse" economic development than countries with "fewer" resources. Wealth of resources may also correspond to "... the likelihood of weak democratic development, corruption, and civil war". High levels of corruption lead to great political instability, because whoever controls the assets (usually the political leaders and the government, in the case of the Democratic Republic of the Congo) can use them for their own benefit. The resources generate wealth, which the leaders use to stay in power "... either through legal means, or coercive ones (e.g. funding militias)". The increased importance of coltan in electronics "occurred as warlords and armies in the eastern Congo converted artisanal mining operations ... into slave labour regimes to earn hard currency to finance their militias," as one anthropological study put it. When much of eastern Congo came under the control of Rwandan forces in the 1990s, Rwanda suddenly became a major exporter of coltan, benefiting from the weakness of the Congolese government. The soaring price "brought in as much as $20 million a month to rebel groups" and other factions trading coltan mined in northeastern Congo, according to a U.N. report.