Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 71409 | Metric tons | NA |
| 2010 | 72000 | Metric tons | 0.83% |
| 2011 | 55976 | Metric tons | -22.26% |
| 2012 | 60000 | Metric tons | 7.19% |
| 2013 | 70000 | Metric tons | 16.67% |