Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 49962 | Metric tons | NA |
| 2010 | 59086 | Metric tons | 18.26% |
| 2011 | 65619 | Metric tons | 11.06% |
| 2012 | 54202 | Metric tons | -17.40% |
| 2013 | 55000 | Metric tons | 1.47% |
