These differences can also be extended to the degree to which international prices will be passed through to the local market, in urban zones that are more integrated into the international economy, pass-through is more likely, and they will have a larger proportion of net food-consuming households. If food prices rise by more than other prices, then expenditure by the poorest population groups will be subject to greater relative inflation. In fact, data show that the rise in food prices seriously erodes the purchasing power of the poorest households: for example, in rural areas of El Salvador, households in 2008 were buying 58% of what they bought 18 months earlier for the same money.