INDIANAPOLIS -- Following the normal pattern of increases, gas prices shot up about 20 cents a gallon at virtually all central Indiana gas stations Tuesday.

The price for a gallon of regular unleaded gas sat at $2.76 a gallon at most stations, up from $2.56 a gallon on Monday.

The pattern over the last few weeks has been drastic increases on Tuesday, followed by incremental decreases for the remainder of the week.

AAA said the national average for a gallon of regular unleaded is $2.52 a gallon, but that report typically runs a couple of days behind real-time prices.

Indiana's average, according to AAA, was $2.61 a gallon, with Indianapolis a little less than that.

This time last year, a gallon of regular unleaded in Indiana cost nearly $4 a gallon and was nearing the all-time high of $4.15 in the Indianapolis area.

Energy experts are blaming the price hikes on surging oil prices, which have nearly doubled since dipping below $35 a barrel in March.

A gallon of gas cost just $1.70 a gallon in December.