Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 65 | Thousand metric tons | NA |
| 2004 | 124.678001403809 | Thousand metric tons | 91.81% |
| 2005 | 106.797996520996 | Thousand metric tons | -14.34% |
| 2006 | 110.753997802734 | Thousand metric tons | 3.70% |
| 2007 | 82.9739990234375 | Thousand metric tons | -25.08% |
| 2008 | 83 | Thousand metric tons | 0.03% |
| 2009 | 9.15200042724609 | Thousand metric tons | -88.97% |
| 2010 | 99.7300033569336 | Thousand metric tons | 989.71% |
| 2011 | 20.4370002746582 | Thousand metric tons | -79.51% |
| 2012 | 45.4070014953613 | Thousand metric tons | 122.18% |
| 2013 | 45 | Thousand metric tons | -0.90% |
