Gas prices have risen significantly over time, starting at 30 cents per gallon in the 1920s and now reaching as high as $4 per gallon today. If oil prices continue on their current trajectory and reach $200 per barrel, gas is predicted to cost $7 per gallon in the future. The United States consumes about 146 billion gallons of gasoline annually and is the largest consumer of gas, while Niue uses the least amount.