"Renewable Energy - Market and Policy Trends in IEA Countries reviews the experience of IEA countries after the oil crisis in the 1970s initiated a surge of investments in renewables research and development. While use of renewables has grown rapidly, they still account for only a small portion of the IEA energy mix. Hydropower, bioenergy and geothermal energy are mature technologies that contribute about 5 - 6% to primary energy supply." (Quoted from site)