Copper prices, a widely followed barometer of global economy activity, have dropped to a six-week low after a drop in demand from the world’s largest copper consumer, China, and a lessened economic outlook for the U.S., the CME group reported on Wednesday.

According to Goldman Sachs (NYSE:GS), copper prices have been weak all through May and June, and prices dipped 3.1 percent to $7,482 per metric ton, which the firm listed as a loss of $236 per metric ton.

“The weak price in our view predominantly reflects poor sentiment towards both current and future global growth, together with an increasing market perception that copper will move into surplus in 2014, or perhaps earlier,” Goldman Sachs said in a statement.

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