| Year | Production (tonnes) | Imports (tonnes) | Exports (tonnes) |
| 2014 | 592,700 | 192,100 | 400 |
| 2015 | 635,700 | 247,400 | 100 |
| 2016 | 639,700 | 334,100 | 100 |
| 2017 | 376,100 | 989,600 | 400 |
| 2018 | 491,100 | 284,200 | 2000 |