Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | Year Ended December 31, | Year Ended December 31, | Year Ended December 31, | Year Ended December 31, | Year Ended December 31, |
| --- | --- | --- | --- | --- | --- |
|  | 2017 | 2016 | 2015 | 2014 | 2013 |
| Revenue passenger miles (in millions) | 217,712 | 213,098 | 209,625 | 202,925 | 194,988 |
| Available seat miles (in millions) | 254,325 | 251,867 | 246,764 | 239,676 | 232,740 |
| Passenger mile yield | 15.99¢ | 15.85¢ | 16.59¢ | 17.22¢ | 16.89¢ |
| Passenger revenue per available seat mile | 13.69¢ | 13.41¢ | 14.10¢ | 14.58¢ | 14.15¢ |
| Total revenue per available seat mile | 16.22¢ | 15.74¢ | 16.50¢ | 16.84¢ | 16.23¢ |
| Operating cost per available seat mile | 13.81¢ | 12.98¢ | 13.33¢ | 15.92¢ | 14.77¢ |
| Passenger load factor | 85.6% | 84.6% | 84.9% | 84.7% | 83.8% |
| Fuel gallons consumed (in millions) | 4,032 | 4,016 | 3,988 | 3,893 | 3,828 |
| Average price per fuel gallon (2) | $1.68 | $1.49 | $1.90 | $3.47 | $3.00 |
| Full-time equivalent employees, end of period | 86,564 | 83,756 | 82,949 | 79,655 | 77,755 |
Question:
How many fuel gallons were consumed by Delta airlines in 2017 ?
Answer:
4,032