Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.

Text: 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 . <table class='wikitable'><tr><td>1</td><td>year</td><td>gallons</td><td>average priceper gallon</td><td>aircraft fuelexpense</td><td>percent of totaloperating expenses</td></tr><tr><td>2</td><td>2018</td><td>4447</td><td>$ 2.23</td><td>$ 9896</td><td>23.6% ( 23.6 % )</td></tr><tr><td>3</td><td>2017</td><td>4352</td><td>1.73</td><td>7510</td><td>19.6% ( 19.6 % )</td></tr><tr><td>4</td><td>2016</td><td>4347</td><td>1.42</td><td>6180</td><td>17.6% ( 17.6 % )</td></tr></table> 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. .
Question: what was the aircraft fuel expense in 2018 plus that in 2017?
Answer: 17406.0
Question: what is the total sum including the expenses from 2016?

user
23586.0
assistant