http://tucsoncitizen.com/miningandyou/2013/10/29/interesting-facts-about-arizona-tucson-and-copper/

On an annual basis, Arizona’s copper mines have contributed more than 50% of the copper mined in the United States since 1961 and accounted for 60 to 70% of our nation’s copper production since 1976.

More than 90% of Arizona’s historic copper production has been derived from mines located within the southern portion of the state.