Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 1280 | Thousand metric tons | NA |
| 2010 | 1804 | Thousand metric tons | 40.94% |
| 2011 | 1181 | Thousand metric tons | -34.53% |
| 2012 | 1132 | Thousand metric tons | -4.15% |
| 2013 | 1500 | Thousand metric tons | 32.51% |
