NEW YORK — The price of oil dropped below $90 per barrel Wednesday, the latest milestone in a weekslong decline brought on by uncertainty surrounding economies from Europe to China.

Benchmark US crude fell by $1.95 to end at $89.90 per barrel. Oil has tumbled more than 15 percent this month and is at its lowest level since Oct. 21.

Analysts say oil is in an extended slump that should lead to cheaper gasoline and other petroleum-based fuels this summer. Gasoline already has dropped by nearly 26 cents per gallon since early April. The national average is now $3.68 per gallon; some experts say it could fall as low as $3.50 by Independence Day. The average price of diesel fuel is below $4 for the first time since February. It’s good news for an economy that has slowed down since last year’s fourth quarter.