Most official economic statistics are compiled at a national level. For example, GDP and employment data is based government tax receipts, inflation is calculated by analyzing changes in the prices of baskets of goods at either wholesale or retail prices, interest rates, exchange rates and money supply are calculated by central banks, and trade figures are normally logged by customs and excise.
Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore, from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original American name columbium), and the tantalum-dominant mineral is tantalite.
Thailand ranked second in tungsten and third in tin production in 2002, and ranked fifth in feldspar and eighth in gypsum in 2001. The country also had considerable resources of diatomite, dolomite, limestone, potash, rock salt, and a wide variety of other industrial minerals.