( CNN ) -- Gas prices have jumped nearly 7 cents a gallon over the past two weeks , reaching a level more than 75 cents higher than they were a year ago , according to a survey published Sunday . The average price for a gallon of self-serve regular is $ 3.57 , the Lundberg Survey found . That 's 6.65 cents higher than the price the same survey found two weeks earlier . The latest spike suggests that the dramatic price increases are slowing down , said publisher Trilby Lundberg . Between February 18 and March 4 , the survey had found an increase of about 33 cents . That hike corresponded to an increase in crude oil prices amid unrest in more than a dozen countries in the Middle East and north Africa , six of which are OPEC members , Lundberg said . The new jump in prices at the pump comes despite a drop in crude oil prices over the past two weeks . Lundberg described that as `` follow-through '' from the previous spike in oil prices . The survey was taken Friday , before several countries began military action against Libya . It is too soon to know what impact events in Libya will have on gasoline prices , Lundberg said Sunday . The Lundberg Survey tabulates prices at thousands of gas stations nationwide . Of the cities included in the latest survey , the lowest average price was in Billings , Montana , at $ 3.27 a gallon . The highest was in San Francisco , California , at $ 3.97 . Here are the average prices in some other cities : . -- Denver , Colorado - $ 3.29 . -- Atlanta , Georgia - $ 3.49 . -- Boston , Massachusetts - $ 3.54 . -- Philadelphia , Pennsylvania - $ 3.56 . -- Portland , Oregon - $ 3.64 . -- Minneapolis , Minnesota - $ 3.52 .
Gas prices have jumped nearly 7 cents a gallon over the past two weeks . The latest spike comes despite a drop in crude oil prices . It is too soon to know how events in Libya will effect gas prices , survey publisher says .