Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 73580 | Metric tons | NA |
| 2010 | 95092 | Metric tons | 29.24% |
| 2011 | 84480 | Metric tons | -11.16% |
| 2012 | 67500 | Metric tons | -20.10% |
| 2013 | 50000 | Metric tons | -25.93% |
