Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 30 | Thousand metric tons | NA |
| 2009 | 28 | Thousand metric tons | -6.67% |
| 2010 | 30 | Thousand metric tons | 7.14% |
| 2011 | 32 | Thousand metric tons | 6.67% |
| 2012 | 33 | Thousand metric tons | 3.13% |
