what was the total aircraft fuel expense from 2016 to 2018 in millions
the following table shows annual aircraft fuel consumption and costs , including taxes , for our mainline and regional operations for 2018 , 2017 and 2016 ( gallons and aircraft fuel expense in millions ) . year gallons average price per gallon aircraft fuel expense percent of total operating expenses .

| Year | Gallons | Average Priceper Gallon | Aircraft FuelExpense | Percent of TotalOperating Expenses |
| :--- | :--- | :--- | :--- | :--- |
| 2018 | 4,447 | $2.23 | $9,896 | 23.6% |
| 2017 | 4,352 | 1.73 | 7,510 | 19.6% |
| 2016 | 4,347 | 1.42 | 6,180 | 17.6% |

as of december 31 , 2018 , we did not have any fuel hedging contracts outstanding to hedge our fuel consumption . as such , and assuming we do not enter into any future transactions to hedge our fuel consumption , we will continue to be fully exposed to fluctuations in fuel prices . our current policy is not to enter into transactions to hedge our fuel consumption , although we review that policy from time to time based on market conditions and other factors . fuel prices have fluctuated substantially over the past several years . we cannot predict the future availability , price volatility or cost of aircraft fuel . natural disasters ( including hurricanes or similar events in the u.s . southeast and on the gulf coast where a significant portion of domestic refining capacity is located ) , political disruptions or wars involving oil-producing countries , economic sanctions imposed against oil-producing countries or specific industry participants , changes in fuel-related governmental policy , the strength of the u.s . dollar against foreign currencies , changes in the cost to transport or store petroleum products , changes in access to petroleum product pipelines and terminals , speculation in the energy futures markets , changes in aircraft fuel production capacity , environmental concerns and other unpredictable events may result in fuel supply shortages , distribution challenges , additional fuel price volatility and cost increases in the future . see part i , item 1a . risk factors 2013 201cour business is very dependent on the price and availability of aircraft fuel . continued periods of high volatility in fuel costs , increased fuel prices or significant disruptions in the supply of aircraft fuel could have a significant negative impact on our operating results and liquidity . 201d seasonality and other factors due to the greater demand for air travel during the summer months , revenues in the airline industry in the second and third quarters of the year tend to be greater than revenues in the first and fourth quarters of the year . general economic conditions , fears of terrorism or war , fare initiatives , fluctuations in fuel prices , labor actions , weather , natural disasters , outbreaks of disease and other factors could impact this seasonal pattern . therefore , our quarterly results of operations are not necessarily indicative of operating results for the entire year , and historical operating results in a quarterly or annual period are not necessarily indicative of future operating results . domestic and global regulatory landscape general airlines are subject to extensive domestic and international regulatory requirements . domestically , the dot and the federal aviation administration ( faa ) exercise significant regulatory authority over air carriers . the dot , among other things , oversees domestic and international codeshare agreements , international route authorities , competition and consumer protection matters such as advertising , denied boarding compensation and baggage liability . the antitrust division of the department of justice ( doj ) , along with the dot in certain instances , have jurisdiction over airline antitrust matters. .

fuel_expense_2018 = 9896
fuel_expense_2017 = 7510
fuel_expense_2016 = 6180
answer = fuel_expense_2018 + fuel_expense_2017 + fuel_expense_2016