Qatar’s surplus dropped to 12.1 billion riyals ($3.3 billion) in October-December last year from 19.4 billion, or 16.4 percent of gross domestic product in the previous three months, the central bank’s preliminary estimates showed.

Revenue almost doubled to 132.3 billion riyals in October-December from the same period of the previous year, bringing cumulative income for the first three fiscal quarters to 146 percent of the 2010/11 plan.

Analysts polled by Reuters in March expected Qatar, whose economy is powering ahead at a double-digit clip, to post a surplus of 11.5 percent of GDP in the whole of the fiscal year that ended in March.

Qatar plans a 19 percent jump in government spending to a six-year high in the current fiscal year, helped by a recent expansion of its gas industry and robust oil prices.

Qatar, one of the world’s top investors through its sovereign wealth fund, has overspent its budget plan in the previous two fiscal years. Its income also largely overshot the initial plan due to conservative oil price estimates.

In its 2010/11 budget, the country penciled in spending worth 117.9 billion riyals and a surplus of 9.7 billion, or 2.7 percent of GDP.

Qatar, which plans to boost infrastructure spending ahead of hosting the 2022 soccer World Cup, assumed an oil price of $55 per barrel in its 2010/11 budget.

Benchmark US crude prices had been hovering between $64 and $107 a barrel during the 2010/11 fiscal year.