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:
|  | 2017 | 2016 | Increase (Decrease) | % Change |
| --- | --- | --- | --- | --- |
| Salaries and related costs | $11,045 | $10,275 | $770 | 7.5 |
| Aircraft fuel | 6,913 | 5,813 | 1,100 | 18.9 |
| Landing fees and other rent | 2,240 | 2,165 | 75 | 3.5 |
| Regional capacity purchase | 2,232 | 2,197 | 35 | 1.6 |
| Depreciation and amortization | 2,149 | 1,977 | 172 | 8.7 |
| Aircraft maintenance materials and outside repairs | 1,856 | 1,749 | 107 | 6.1 |
| Distribution expenses | 1,349 | 1,303 | 46 | 3.5 |
| Aircraft rent | 621 | 680 | (59) | (8.7) |
| Special charges | 176 | 638 | (462) | NM |
| Other operating expenses | 5,657 | 5,421 | 236 | 4.4 |
| Total operating expenses | $34,238 | $32,218 | $2,020 | 6.3 |
Question:
Find the operating expense of Aircraft rental fees for United Airlines in 2016
Answer:
680