Gas prices are expected to fall below the $2 mark across the nation for the first time since 2009.

According to AAA pump prices have fallen for 29 of the past 31 days. As of Monday the national average is less than a penny higher than the 2015 low (January 26), and should soon fall below the $2 per gallon mark for the first time since 2009. It said Monday’s average price of $2.03 represents a savings of one cent per gallon on the week and 19 cents on the month. Significant yearly savings persist, and gas prices are discounted by 65 cents per gallon compared to this same date last year.

Missouri’s average for regular unleaded Monday was $1.81 a gallon, the same as this time last week and 28 cents lower than a month ago. In St. Joseph the average came in at $1.79, 1 cent lower than a week ago and a drop of 27 cents in a month.

AAA said OPEC’s decision at its meeting last week to sustain its current production levels sent ripples through the global oil market and has contributed to lower oil prices. The cartel is not scheduled to reconvene until June 2016, and in the interim the imbalance between supply and demand will likely persist.