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, | Increase (Decrease) |
| --- | --- | --- | --- |
|  | 2019 | 2018 |  |
| Revenue passenger miles (millions) (a) | 241,252 | 231,160 | 4.4% |
| Available seat miles (millions) (b) | 285,088 | 282,054 | 1.1% |
| Passenger load factor (percent) (c) | 84.6 | 82.0 | 2.6pts |
| Yield (cents) (d) | 17.41 | 17.60 | (1.0)% |
| Passenger revenue per available seat mile (cents)  (e) | 14.74 | 14.42 | 2.2% |
| Total revenue per available seat mile (cents) (f) | 16.05 | 15.79 | 1.7% |
| Aircraft at end of period  (g) | 1,547 | 1,551 | (0.3)% |
| Fuel consumption (gallons in millions) | 4,537 | 4,447 | 2.0% |
| Average aircraft fuel price including related taxes (dollars per gallon) | 2.07 | 2.23 | (6.9)% |
| Full-time equivalent employees at end of period | 133,700 | 128,900 | 3.7% |
| Operating cost per available seat mile (cents) (h) | 14.98 | 14.85 | 0.9% |
Question:
How much did American's yield per passenger mile change in 2019 compared to 2018?
Answer:
(1.0)%