Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 3 | Thousand metric tons | NA |
| 2004 | 3 | Thousand metric tons | 0.00% |
| 2005 | 1.81400001049042 | Thousand metric tons | -39.53% |
| 2006 | 1.79999995231628 | Thousand metric tons | -0.77% |
| 2007 | 1.90199995040894 | Thousand metric tons | 5.67% |
| 2008 | 1.66799998283386 | Thousand metric tons | -12.30% |
| 2009 | 1.84700000286102 | Thousand metric tons | 10.73% |
| 2010 | 2.23099994659424 | Thousand metric tons | 20.79% |
| 2011 | 2.29999995231628 | Thousand metric tons | 3.09% |
| 2012 | 2.29999995231628 | Thousand metric tons | 0.00% |
