That year, high-income countries had the highest material footprint per capita (approximately 27 metric tons per person), 60 per cent higher than the upper-middle-income countries (17 metric tons per person) and more than 13 times the level of low-income countries (2 metric tons per person). The material footprint of high-income countries is greater than their domestic material consumption, indicating that consumption in those countries relies on materials from other countries through international supply chains. On a per-capita basis, high-income countries rely on 9.8 metric tons of primary materials extracted elsewhere in the world.