The given line graph shows the average cost of the metals in 2014 in percentages. Overall, we can clearly see that the monthly changes are enormous, there are some significant depths in July and October, boosts in January.
Comparing, copper, nickel and zinc sales we spectating their prices changing depending on seasons. From January to March there is dramatically fall in each market, but the most was on nickel about 5% and copper in 1,5% and stayed stable April, while zinc showed up and down trend from February to July loosing 3%, Nickel also showed same trend and stayed at -3%. Next half of the year, their prices increased and remained nickel at -1%, zinc at -0,5%, copper 1%. Then, there was stable demand from June to September; after this, all of them showed about -0,5% in October, that consequently was ended by growth of the prices in range of 0,5 and 1,5% each. Last month was also stable, and mostly showed slight increase.
In conclusion, I would say that the market prices of these metals remained at the same price as in previous year except Nickel which actually showed decrease in 5% in a year.