This share is expected to continue to increase to at least two thirds over the coming decades. At present, 2.7 billion people continue to rely on traditional, non-commercial fuels typical for pre-industrial societies. They use only between 15 and 50 GJ of primary energy per capita, delivering about 2-5 GJ of per capita in useful energy services. Growth of per capita energy use in developing countries has accelerated since 1975, whereas use in developed countries has stagnated (figure II.2).