Thanks for the question.

Data on the cement was sourced by individually checking cement prices of each nation from the internet. To validate the data, prices was rechecked by comparing national cement firm’s prices. In the case of the United States, Cement prices are quoted per ton. Therefore, the price was divided by 20.

On the case of sugar, global prices of raw sugar are quoted on reuters as $555 per ton. To check the Nigerian price, the Procurement Director of A.G. Leventis assisted with the figure.

Most of the values were found in local currencies. They were rebased to Naira on the CBN approved exchange rates. For example, the value of Dollar to Naira, was at the CBN rate of 304, rather than the black market rate of 315.

Hope the explanation, revealed the sources of data used in the charts.