The increase in warfare was fueled by huge imports of guns and ammunition, which the Europeans exchanged for slaves. By 1730 about 180,000 guns were being imported every year just along the West African coast, and between 1750 and the early nineteenth century, the British alone sold between 283,000 and 394,000 guns a year. Between 1750 and 1807, the British sold an extraordinary 22,000 tons of gunpowder, making an average of about 384,000 kilograms annually, along with 91,000 kilograms of lead per year.
