In these countries, the fossil-fuel sector generally provides more than half of all central government revenues (and more than 80 per cent in South Sudan), equivalent to some 10-25 per cent of GDP. The sole exception is the Sudan, where oil-sector revenues amount to only 2.4 per cent of GDP, although even here this represents 20.6 per cent of central government revenues (table 2.7). This makes it difficult for Governments to plan their expenditure over the medium and long term and may force spending cuts in times of declining fuel prices.