Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 13359 | Metric tons | NA |
| 2010 | 13296 | Metric tons | -0.47% |
| 2011 | 17792 | Metric tons | 33.81% |
| 2012 | 31559 | Metric tons | 77.38% |
| 2013 | 31600 | Metric tons | 0.13% |
