Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2008 | 799 | Thousand metric tons | NA |
| 2009 | 709 | Thousand metric tons | -11.26% |
| 2010 | 820 | Thousand metric tons | 15.66% |
| 2011 | 1303 | Thousand metric tons | 58.90% |
| 2012 | 1368 | Thousand metric tons | 4.99% |
| 2013 | 1300 | Thousand metric tons | -4.97% |
