Russian oil output is expected to fall 8 percent in the next two years, the steepest fall since President Vladimir Putin took power at the end of 1990s, as low prices force companies to cut back on drilling in Siberia, a top Russian oil executive said, quoted by Reuters.

Leonid Fedun, vice-president and a large shareholder in Russia’s top private oil firm Lukoil, said the drop could amount to as much as 800,000 barrels per day (bpd) by the end of 2016.

His forecast is one of the most pessimistic yet by a Russian oil executive since the country was hit by sanctions and a steep drop in oil prices.

By contrast, the energy ministry expects Russian output to be steady this year at around 10.56-10.60 million bpd. Oil and gas sales account for half of Russia’s budget revenue.

Russian oil output halved in the 1990s following the collapse of the Soviet Union but has recovered by more than 70 percent on the back of high oil prices since Putin took over as president in 1999. Russia is the world’s largest oil producer.

Sanctions imposed on the country over its role in the Ukraine crisis have drastically limited Russian firms’ access to Western capital and technology over the past year while low oil prices are forcing them to slash exploration budgets.

“Everyone will reduce production because everyone is reducing drilling,” Fedun said. He said he expected drilling in Siberia to drop by as much as 15-20 percent.

Fedun said Lukoil’s output was likely to stay flat or drop slightly in 2015 as the company was drilling fewer wells in Siberia. In 2016, it could recover as it brings new fields in Russia on-stream, he said.