Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2009 | 2.30100011825562 | Thousand metric tons | NA |
| 2010 | 1.34899997711182 | Thousand metric tons | -41.37% |
| 2011 | 3.5 | Thousand metric tons | 159.45% |
| 2012 | 3.79999995231628 | Thousand metric tons | 8.57% |
| 2013 | 4 | Thousand metric tons | 5.26% |
