Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 256.5 | Thousand metric tons | NA |
| 2010 | 523.351013183594 | Thousand metric tons | 104.04% |
| 2011 | 745.814025878906 | Thousand metric tons | 42.51% |
| 2012 | 755 | Thousand metric tons | 1.23% |
| 2013 | 750 | Thousand metric tons | -0.66% |
