Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2010 | 1.1690000295639 | Metric tons | NA |
| 2011 | 1.39800000190735 | Metric tons | 19.59% |
| 2012 | 1.5 | Metric tons | 7.30% |
