Dollar Strength Fuels Commodities' Worst Year Since 2008: Chart

The Bloomberg Commodity Spot Index, a basket of commodities from gold to cotton, has dropped 19 percent this year, the worst performance since 2008, when the financial crisis caused a 29 percent plunge.

Part of the reason has been the stronger greenback -- up 9 percent this year against a group of global currencies. Commodities are priced in U.S. dollars making them more expensive for holders of other currencies.

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