DUBAI (Reuters) – Non-OPEC oil producer Oman posted a budget surplus of 1.58 billion rials ($4.1 billion) in 2008, the highest this decade, as revenues from oil exports surged, official data showed.

Total state revenues rose 34.9 percent to 7.98 billion rials while expenditures by the Gulf state climbed 8.9 percent to 6.4 billion rials, the Ministry of National Economy said in a monthly report on its website.

The surplus was the highest since at least 2001, according to historical data posted on the central bank’s website.

Gulf Arab oil exporters posted record budget surpluses last year after crude prices rallied to a record of almost $150 a barrel last July.

Prices subsequently collapsed more than $100 a barrel before the end of the year as the global financial crisis weakened energy demand and brought to an end a regional economic boom that had been supported by rallying oil prices.

In January, Oman projected a $2.1 billion budget deficit for 2009 based on an average oil price of $45 a barrel.

Oman’s 2008 net oil revenue surged 48.4 percent to 5.46 billion rials, the ministry said. Gas revenues advanced 12.2 percent to 909.8 million rials, while customs duties revenues added 30.6 percent to 208.5 million rials.

The Gulf state’s surplus compared with 40.2 million rials in 2007.

Oman invested more money on developing ministries and oil production in 2008, with total investment expenditure climbing to 2.08 billion rials from 1.7 billion riyals, the ministry added.