(Bloomberg) — Oil gained at the start of the week’s trading on signs that the crude market is tightening because of the global energy crunch.

West Texas Intermediate closed in on $75 a barrel after a run of five weekly gains, while hit the highest level since October 2018. Stockpiles in the United States are near their lowest level for three years, and inventories have been declining. At the same time, a rally in looks set to drive demand for oil as users switch fuels.

Over the past year, oil prices have risen by more than 80 percent as world demand has recovered from the global pandemic. Supply-side, Russia and the Organization of Petroleum Exporting Countries have been slowly easing production curbs, which has allowed markets to tighten. Extreme weather conditions in the U.S. have also impacted local production.

Market watchers are reporting further increases in prices at the onset of winter in the northern hemisphere. Among them, Goldman Sachs Group Inc (NYSE:). said the market’s deficit was larger than expected, and raised its year-end Brent forecast by $10 to $90 a barrel.

The spreads of key market indicators have increased, indicating that traders are more optimistic about the future. Brent’s prompt spread was 85 cents a barrel in backwardation, a bullish pattern with near-dated prices above those further out. That’s up from 61 cents a week ago.

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