Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 49 | Thousand metric tons | NA |
| 2009 | 351 | Thousand metric tons | 616.33% |
| 2010 | 367 | Thousand metric tons | 4.56% |
| 2011 | 373 | Thousand metric tons | 1.63% |
| 2012 | 360 | Thousand metric tons | -3.49% |
| 2013 | 354 | Thousand metric tons | -1.67% |
