The national average price for a gallon of gasoline has fallen 2.6 cents per gallon over the last week to $2.88 per gallon, according to GasBuddy data compiled from more than 10 million individual price reports. The national average price of diesel moved higher, adding 1.6 cents to an average of $3.29 per gallon.

“The last week has seen a flurry of events to keep an eye on, while the recent drop in oil prices materialized at pumps across the country, but nowhere have the declines been as large as Great Lakes states,” said Patrick DeHaan, head of petroleum analysis for GasBuddy.

“Great Lakes states have wreaked havoc on the national average, sending it down considerably as stations there have passed along the recent drop in oil prices relatively quickly. However, while Great Lakes motorists were seeing lower prices, average prices along the West Coast, mainly in Washington and Oregon, have started to jump after a natural gas pipeline explosion last week pushed some refineries to close. In addition, events in Saudi Arabia bear monitoring as the West claims the Kingdom is behind the disappearance of a Washington Post journalist and could rile tensions between the world’s largest oil consumer and one of the world’s largest oil producers. I believe gas prices in most areas East of the Rockies will drift lower, but keep an eye out on these new developments. I don’t know that I’ve ever seen autumn so rife with possible volatility at the pump as we’re seeing now.”

Retail gasoline prices have moved lower following oil’s drop last week on concerns over slowing global growth as trade battles heat up. Oil prices opened Monday’s session at $71 per barrel, a $3 loss in the last week, following the Dow Jones average slipping 4%. Fresh geopolitical concerns over the disappearance of Washington Post’s Jamal Khashoggi in Turkey add to some uncertainty for oil’s movement in the week ahead. The U.S. and Saudi Arabia had traded some harsh words before settling down with the Saudi Arabia King officially opening an investigation. The situation could pose wide implications for oil supply and trade as President Trump promised to be severe should the U.S. find the Kingdom responsible.

For drivers trying to make sense out of the situation, the effects of the market downdraft last week may be spilling over in terms of slightly lower pump prices. According to GasBuddy, while average prices fell in the last week, they are still up 2.5 cents versus last month and up more than 42 cents a gallon in contrast to prices paid on this very day in 2017. For diesel, which has seen a stellar rise this year, average prices which clocked in at $2.72 a gallon this time last year, are now up a significant 57 cents to just under $3.30 a gallon.

Back stateside, average gas prices fell in 43 states while rising in 7. Prices were led lower by Great Lakes states, which saw the biggest drops in average prices: Michigan fell 12.3 cents, Ohio fell 11.1 cents, Indiana fell 10.0 cents, Illinois fell 7.6 cents and Kentucky fell 6.1 cents.

States with the lowest average gas prices: South Carolina ($2.60), Mississippi ($2.60), Alabama ($2.62), Louisiana ($2.63) and Oklahoma ($2.64).

States with the highest average gas prices: Hawaii ($3.84), California ($3.82), Washington ($3.52), Oregon ($3.37) and Alaska ($3.35).