Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 52 | Thousand metric tons | NA |
| 2010 | 52 | Thousand metric tons | 0.00% |
| 2011 | 27 | Thousand metric tons | -48.08% |
| 2012 | 27.9540004730225 | Thousand metric tons | 3.53% |
| 2013 | 28 | Thousand metric tons | 0.16% |
