Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 6.53599977493286 | Thousand metric tons | NA |
| 2010 | 13.4209995269775 | Thousand metric tons | 105.34% |
| 2011 | 23.3950004577637 | Thousand metric tons | 74.32% |
| 2012 | 11.9799995422363 | Thousand metric tons | -48.79% |
| 2013 | 15 | Thousand metric tons | 25.21% |
