Trade costs have been decreasing from 1995 to 2010, but more rapidly in developed countries than in developing ones. This makes it harder for developing countries, especially in Sub-Saharan Africa and low-income countries, to trade with others. Factors like maritime transport and logistics performance greatly affect trade costs, sometimes even more than distance. Trade policies, both traditional and non-traditional, also play a big role in shaping how easy or difficult it is for countries to trade with each other.