Although Kenya is the most industrially developed country in the African Great Lakes region, manufacturing still accounts for only 14% of the GDP. Industrial activity, concentrated around the three largest urban centres, Nairobi, Mombasa and Kisumu, is dominated by food-processing industries such as grain milling, beer production, and sugarcane crushing, and the fabrication of consumer goods, e.g., vehicles from kits. There is a cement production industry.[citation needed] Kenya has an oil refinery that processes imported crude petroleum into petroleum products, mainly for the domestic market. In addition, a substantial and expanding informal sector commonly referred to as Jua Kali engages in small-scale manufacturing of household goods, motor-vehicle parts, and farm implements.[citation needed]