Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 42.2000007629395 | Thousand metric tons | NA |
| 2009 | 33 | Thousand metric tons | -21.80% |
| 2010 | 36 | Thousand metric tons | 9.09% |
| 2011 | 14 | Thousand metric tons | -61.11% |
| 2012 | 21 | Thousand metric tons | 50.00% |
| 2013 | 20 | Thousand metric tons | -4.76% |
