About 118 tonnes of germanium was produced in 2011 worldwide, mostly in China (80 t), Russia (5 t) and United States (3 t). Germanium is recovered as a by-product from sphalerite zinc ores where it is concentrated in amounts as great as 0.3%, especially from low-temperature sediment-hosted, massive Zn–Pb–Cu(–Ba) deposits and carbonate-hosted Zn–Pb deposits. A recent study found that at least 10,000 t of extractable germanium is contained in known zinc reserves, particularly those hosted by Mississippi-Valley type deposits, while at least 112,000 t will be found in coal reserves. In 2007 35% of the demand was met by recycled germanium.