Since the early 1990s, Sub-Saharan Africa has become a region of major importance to global oil markets. Africa's rise is primarily due to the deep off-shore technological revolution, which has made a series of large discoveries in the wider Gulf of Guinea (Angola, Nigeria, Equatorial Guinea) possible. Africa is one of the very few regions outside the Persian Gulf and Russia where there is a potential for a significant increase in oil production capacity – hence its prominent position in both the international oil companies' growth strategies and in the United States' global energy policy.