Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 14615.099609375 | Thousand metric tons | NA |
| 2010 | 10537 | Thousand metric tons | -27.90% |
| 2011 | 12625 | Thousand metric tons | 19.82% |
| 2012 | 10845 | Thousand metric tons | -14.10% |
| 2013 | 12210.08203125 | Thousand metric tons | 12.59% |
