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 (a) | 2015 | 2014 | 2013 |
| --- | --- | --- | --- | --- | --- |
| Mainline passenger revenue | 74% | 69% | 70% | 70% | 70% |
| Regional passenger revenue | 12% | 15% | 15% | 15% | 16% |
| Other revenue | 13% | 14% | 13% | 13% | 12% |
| Freight and Mail revenue | 1% | 2% | 2% | 2% | 2% |
| Total | 100% | 100% | 100% | 100% | 100% |
Question:
What is the share of regional revenue of passengers for Alaska Airlines in 2014?
Answer:
15%