Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 4200 | Thousand metric tons | NA |
| 2004 | 5900 | Thousand metric tons | 40.48% |
| 2005 | 138 | Thousand metric tons | -97.66% |
| 2006 | 120 | Thousand metric tons | -13.04% |
| 2007 | 117 | Thousand metric tons | -2.50% |
| 2008 | 100 | Thousand metric tons | -14.53% |
| 2009 | 85 | Thousand metric tons | -15.00% |
| 2010 | 271 | Thousand metric tons | 218.82% |
| 2011 | 287 | Thousand metric tons | 5.90% |
| 2012 | 124 | Thousand metric tons | -56.79% |
| 2013 | 145 | Thousand metric tons | 16.94% |
