Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 48.4000015258789 | Thousand metric tons | NA |
| 2010 | 44 | Thousand metric tons | -9.09% |
| 2011 | 48 | Thousand metric tons | 9.09% |
| 2012 | 50 | Thousand metric tons | 4.17% |
| 2013 | 51 | Thousand metric tons | 2.00% |
