Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 5.40000009536743 | Thousand metric tons | NA |
| 2004 | 4.55000019073486 | Thousand metric tons | -15.74% |
| 2005 | 5.09999990463257 | Thousand metric tons | 12.09% |
| 2006 | 5.69999980926514 | Thousand metric tons | 11.76% |
| 2007 | 6.30200004577637 | Thousand metric tons | 10.56% |
| 2008 | 6.5460000038147 | Thousand metric tons | 3.87% |
| 2009 | 30.7000007629395 | Thousand metric tons | 368.99% |
| 2010 | 70.25 | Thousand metric tons | 128.83% |
| 2011 | 7 | Thousand metric tons | -90.04% |
| 2012 | 7 | Thousand metric tons | 0.00% |
| 2013 | 33 | Thousand metric tons | 371.43% |
