Iraqi revenue generated from oil exports in August was lower than the previous month by nearly $1 billion in part because of low oil prices, data show.

The ministry, using data from a federal marketing company, said total crude oil exports for August was 95.4 million barrels. Roughly 98 percent of those exports left the country from southern ports, with the remainder traveling north across the border to a sea port in Turkey.

A monthly newsletter from the Organization of Petroleum Exporting Countries said the federal government was making a "special effort" to increase exports through southern ports to compensate for delays from inclement weather. The Oil Ministry said southern ports faced short-term "technical obstacles" that interrupted some exports.

A spokesman for the ministry said total exports brought in $3.87 billion in revenue for the government in August, when oil prices hovered in the upper-$40 per barrel range. OPEC said export revenues in July were $4.91 billion and $5.3 billion in June.

"Crude in July was sold at an average price of $50.9 per barrel, some $5.30 per barrel below the price average for the previous month," OPEC said. "The export price contained in the Iraqi budget stands at $56 per barrel."

A review of the Iraqi economy from the World Bank finds the budget depends heavily on crude oil exports and the energy sector in general. A government deficit in 2015 is expected at 11 percent of the $220.5 billion gross domestic product reported in 2014.

Sectors outside the oil industry account for less than half of the Iraqi economy. Lingering conflict tied to the rise of the terrorist group calling itself the Islamic State has led to the destruction of key national infrastructure and resulted in a decline in business confidence and disruption in trade, the World Bank said.

"Non-oil GDP growth declined by 5.2 percent in 2014," the bank said. "In 2015, real GDP growth is projected to decline by 1 percent due to lower oil prices and the impact of the conflict."