Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1330 | Thousand metric tons | NA |
| 2004 | 890 | Thousand metric tons | -33.08% |
| 2005 | 930 | Thousand metric tons | 4.49% |
| 2006 | 1370 | Thousand metric tons | 47.31% |
| 2007 | 1280 | Thousand metric tons | -6.57% |
| 2008 | 1280 | Thousand metric tons | 0.00% |
| 2009 | 2942.08471679688 | Thousand metric tons | 129.85% |
| 2010 | 3049.51782226563 | Thousand metric tons | 3.65% |
| 2011 | 3302.25 | Thousand metric tons | 8.29% |
| 2012 | 3300 | Thousand metric tons | -0.07% |
| 2013 | 3300 | Thousand metric tons | 0.00% |
