Oil isn't the only commodity that's gotten cheaper.
From nickel to soybean oil, plywood to sugar, global commodity prices have been on a steady decline as the world's economy has lost momentum. That lower demand helps explain, in part, why nearly everything from crude oil to cotton has been getting cheaper.
Sure, some commodity prices are rising. Local supply constraints have pushed prices higher in some parts of the world; transportation costs can also have a big impact on local prices. In the U.S., for example, a drought in California caused the price of vegetables and other food products to spike last year.
Prices are also rising for some commodities, especially meats such as beef and chicken, thanks to growing demand from an expanding middle class in the developing world.
But the global cost of most commodities has been on a long-term, downward trend since the Great Recession. The chart below is based on global prices, in dollars, assembled by the World Bank.
Now, as much of the world slogs through a faltering recovery, there are fears that falling prices in slow-moving economies such as Europe and Japan could spark and extended period of deflation, when the consumer prices of finished goods fall over an extended period.