比如，非洲公路运输关税据估计在每吨千米0.05—0.13美元，而所有发展中国家的平均水平为0.01—0.05美元。
For example, road transport tariffs across Africa are estimated at $0.05-$0.13 per ton-kilometer, compared to the average of $0.01-$0.05 for all developing countries.