Religious and ethnic divisions in Nigeria have led to conflict. When northern Muslim military officers staged a coup, the Ibo people -- natives of southeastern Nigeria -- waged a war for independence. ... But ethnic and religious divisions have regularly led to conflict since then.
So, I probably shouldn't put this in the 'Answer' section, but first off, Roman, second off, whats the question precisely?
Most of the time; less than always, but more than occasionally.
Elections in 1992 were canceled in Algeria when it appeared that Islamic fundamentalists would win.