Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 4.3769998550415 | Thousand metric tons | NA |
| 2004 | 6.44399976730347 | Thousand metric tons | 47.22% |
| 2005 | 8.20699977874756 | Thousand metric tons | 27.36% |
| 2006 | 4.09999990463257 | Thousand metric tons | -50.04% |
| 2007 | 1 | Thousand metric tons | -75.61% |
| 2008 | 1.59700000286102 | Thousand metric tons | 59.70% |
| 2009 | 4.0460000038147 | Thousand metric tons | 153.35% |
| 2010 | 4 | Thousand metric tons | -1.14% |
| 2011 | 3.5 | Thousand metric tons | -12.50% |
| 2012 | 3 | Thousand metric tons | -14.29% |
| 2013 | 3 | Thousand metric tons | 0.00% |
