Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1341.75500488281 | Thousand metric tons | NA |
| 2004 | 1269.208984375 | Thousand metric tons | -5.41% |
| 2005 | 1270 | Thousand metric tons | 0.06% |
| 2006 | 1151.54699707031 | Thousand metric tons | -9.33% |
| 2007 | 8823 | Thousand metric tons | 666.19% |
| 2008 | 10244 | Thousand metric tons | 16.11% |
| 2009 | 1000 | Thousand metric tons | -90.24% |
| 2010 | 1036.05200195313 | Thousand metric tons | 3.61% |
| 2011 | 1000 | Thousand metric tons | -3.48% |
| 2012 | 1000 | Thousand metric tons | 0.00% |
| 2013 | 1000 | Thousand metric tons | 0.00% |
