If you look at long term inflation adjusted copper price it has mainly fluctuated around $2-$3 US$/lb with outlier years. China's GDP growth rate has been fairly strong from the 1980's ranging form around 5% to 14% approx. Unless something has changed you would think it would be normal for copper to go down around $2 in times of poor demand (high supply) and increase to around $3 in times of good demand (low supply). Its all to do with future demand and supply though obviously.
