Most prices are regulated by the state, but food is the largest item of expenditure for most North Koreans, and domestic agricultural production therefore dictates the underlying rate of consumer price inflation. Volatility in the size of harvests is likely in the forecast period, as the country has repeatedly proved itself ill placed to take steps to offset the impact of natural disasters, and its ability to invest in agriculture is limited by its overall lack of resources. Consequently, periods of very rapid inflation are possible. This trend could be heightened by ill-judged monetary policies-inflation has still not come back down to its previous rate since the failed currency reform of 2009. North Korea imports most of its oil. Global oil prices are expected to rise further in the forecast period, pushing up the North's energy costs. More generally, the cost of imported inputs could fluctuate dramatically, depending on the trade policies adopted by China and South Korea, the two main countries that export to the North.