CASE: China's Currency vs. the Dollar

How much has the Chinese yuan x US dollar exchange rate varied over the past ten years? Has the range been similar to the change in exchange rate in say the dollar vs. the euro over the same ten years? Do you think China has been managing its exchange rate?

Some people in the US have been calling for China to increase the value of its currency vs. The U.S. dollar. If the Chinese currency were to go up vs. the U.S. dollar, how might this affect a U.S. exporter to China -- like Boeing or Oregon's Benchmade knives? How would the higher Chinese currency affect a U.S. importer from China -- like Walmart? How might it affect U.S. employment?