Though the answer to this question can vary from one region of the country to another, the most plausible answer is lack of competition on the supply side and high switching costs on the demand side.

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The trade could grow even more quickly than that over the next few years, thanks partly to the pace at which China's foreign trade is growing, and partly to the speed with which its companies are switching to containers and learning to manage their supply chains more efficiently.

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He changed materials, switching in 1996 from conventional to organic cotton despite the fact that it initially tripled his supply costs because it was less harmful to the environment.

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