The graph below shows the average monthly change in the prices of three metals during 2014.

The provided line chart illustrates the average change of proportion in the cost compared with the previous month of three metals during one year in 2014. They are categorized as copper, nickel, and zinc.

Overall

, The proportion of the two categories except copper to the prices witnessed fluctuation.

In addition

, what stands out is that all categories had the highest decline in the middle of the year.

Firstly

, nickel accounted for 6% of change prices in January, but plummeted to half in June.

This

figure slightly increased to -1% before It levelled off in the next 3 months which

then

reached up to 1% in December. A similar trend happened in copper, It counted for 2% in the beginning, but decreased incrementally to below 0%.

This

figure was still unchanged until the

last

two months which bounced back at the position start.

Lastly

, nickel was calculated for 1% in the first month,

however

,

this

shape reached a peak in February at 3% before it declined gradually to -1% in June. In November, zink surpassed the other two categories, making it the top position among others.