Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 71.2760009765625 | Thousand metric tons | NA |
| 2010 | 77.4000015258789 | Thousand metric tons | 8.59% |
| 2011 | 80 | Thousand metric tons | 3.36% |
| 2012 | 91.0210037231445 | Thousand metric tons | 13.78% |
| 2013 | 126.399002075195 | Thousand metric tons | 38.87% |
