Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 1300 | Thousand metric tons | NA |
| 2010 | 1900 | Thousand metric tons | 46.15% |
| 2011 | 2200 | Thousand metric tons | 15.79% |
| 2012 | 2100 | Thousand metric tons | -4.55% |
| 2013 | 2100 | Thousand metric tons | 0.00% |
