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:
|  | 2019 | 2018 | Increase (Decrease) | % Change |
| --- | --- | --- | --- | --- |
| Salaries and related costs | $12,071 | $11,458 | $613 | 5.3 |
| Aircraft fuel | 8,953 | 9,307 | (354) | (3.8) |
| Regional capacity purchase | 2,849 | 2,649 | 200 | 7.6 |
| Landing fees and other rent | 2,543 | 2,449 | 94 | 3.8 |
| Depreciation and amortization | 2,288 | 2,165 | 123 | 5.7 |
| Aircraft maintenance materials and outside repairs | 1,794 | 1,767 | 27 | 1.5 |
| Distribution expenses | 1,651 | 1,558 | 93 | 6.0 |
| Aircraft rent | 288 | 433 | (145) | (33.5) |
| Special charges | 246 | 487 | (241) | NM |
| Other operating expenses | 6,275 | 5,801 | 474 | 8.2 |
| Total operating expenses | $38,958 | $38,074 | $884 | 2.3 |
Question:
what was the percentage rise in total operating expenses for United airlines from 2018 to 2019?
Answer:
2.3