The average cost of gasoline in the year 2000 was $1.51 per gallon. Since then, gas prices have continued to steadily increasing, and in 2015, they average over $2.50 per gallon
Gas is an extremely unstable commodity whose price tends to fluctuate due to several factors including weather events and geopolitical risks. For example, if a war breaks out in an area that exports a lot of gasoline, the price of gas can increase globally. This also works in reverse. If a country or corporation discovers gas, the price of gas can decrease globally because of the increase in supply.