Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 106 | Thousand metric tons | NA |
| 2009 | 127 | Thousand metric tons | 19.81% |
| 2010 | 226 | Thousand metric tons | 77.95% |
| 2011 | 249 | Thousand metric tons | 10.18% |
| 2012 | 249 | Thousand metric tons | 0.00% |
| 2013 | 250 | Thousand metric tons | 0.40% |
