If the economists want us to pay for reuse, then
legally speaking, we still can use this data in our own artistic illustration by citing the source – in this case – Economist.com
Hence, you do not have to do anything further here.
At the end, NYP will have the final say on all copyright issues.
If NYP disagree with the above, then we may have to take out the economist data later on. (for all cases)
All for the best,