Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 67 | Thousand metric tons | NA |
| 2003 | 350 | Thousand metric tons | 422.39% |
| 2004 | 106.139999389648 | Thousand metric tons | -69.67% |
| 2005 | 349.588989257813 | Thousand metric tons | 229.37% |
| 2006 | 226.800003051758 | Thousand metric tons | -35.12% |
| 2007 | 495.334991455078 | Thousand metric tons | 118.40% |
| 2008 | 500 | Thousand metric tons | 0.94% |
| 2009 | 18.7329998016357 | Thousand metric tons | -96.25% |
| 2010 | 58.923999786377 | Thousand metric tons | 214.55% |
| 2011 | 20.2150001525879 | Thousand metric tons | -65.69% |
| 2012 | 99.6279983520508 | Thousand metric tons | 392.84% |
| 2013 | 117.619003295898 | Thousand metric tons | 18.06% |
