Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 113 | Thousand metric tons | NA |
| 2010 | 102 | Thousand metric tons | -9.73% |
| 2011 | 136 | Thousand metric tons | 33.33% |
| 2012 | 143 | Thousand metric tons | 5.15% |
| 2013 | 150 | Thousand metric tons | 4.90% |
