I am not sure about these numbers that were published by the Ministry of Economy in El Salvador as I think our prices in Panama remain high despite the cost of crude oil.

Price of a gallon of regular gasoline: Panama $ 2.41, El Salvador, $2.54, Guatemala $2.59, Nicaragua $3.23, Honduras, $3.20, Costa Rica, $3.76.
The Ministry of Economy announced on November 23 that the reference prices for gasoline, effective from November 24 to December 7, 2015, will experience reductions of up to – $0.05, note that this is the ninth consecutive redution in regular and special gasoline; while diesel also features new low prices.

Variations in international prices of refined products (gasoline and diesel) over the last few weeks have influenced prices in Central America, allowing El Salvador to be located first with the lowest prices in gasoline, and second with the lowest price in diesel.

Average prices of gasoline and diesel in Central America:

Country Diesel – Regular – Special
El Salvador 2,39- 2.54 to 2.74
Guatemala 2,23- 2.59 to 2.79
Honduras 2,86 – 3.20 to 3.49
Nicaragua 2,89 – 3.23 to 3.45
Costa Rica 3,15 – 3.76 to 3.93
Panama 2.23 to 2.41 – 2.71 (data taken from Latinol.com).