| 年份 | 资本成本 | 税前债务资本成本 | 税后债务资本成本 | 权益资本成本 |
| 2012 | 9.92% | 4.58% | 3.75% | 10.42% |
| 2013 | 8.10% | 3.17% | 2.67% | 8.64% |
| 2014 | 6.97% | 3.84% | 3.23% | 7.66% |
| 2015 | 9.22% | 5.54% | 4.67% | 10.41% |
| 2016 | 11.39% | 4.49% | 3.79% | 13.12% |