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 | Gallons | Average  Price per Gallon | Aircraft  Fuel Expense | Percent of Total Operating 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% |
Question:
How much fuel did American Airlines use in 2018?
Answer:
4,447