Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 6834 | Thousand metric tons | NA |
| 2003 | 1901 | Thousand metric tons | -72.18% |
| 2004 | 2500 | Thousand metric tons | 31.51% |
| 2005 | 3000 | Thousand metric tons | 20.00% |
| 2006 | 3500 | Thousand metric tons | 16.67% |
| 2007 | 4500 | Thousand metric tons | 28.57% |
| 2008 | 6453 | Thousand metric tons | 43.40% |
| 2009 | 7000 | Thousand metric tons | 8.48% |
| 2010 | 8000 | Thousand metric tons | 14.29% |
| 2011 | 10000 | Thousand metric tons | 25.00% |
| 2012 | 10000 | Thousand metric tons | 0.00% |
