Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 2000 | Thousand metric tons | NA |
| 2003 | 2000 | Thousand metric tons | 0.00% |
| 2004 | 2000 | Thousand metric tons | 0.00% |
| 2005 | 2000 | Thousand metric tons | 0.00% |
| 2006 | 2000 | Thousand metric tons | 0.00% |
| 2007 | 2000 | Thousand metric tons | 0.00% |
| 2008 | 2000 | Thousand metric tons | 0.00% |
| 2009 | 735 | Thousand metric tons | -63.25% |
| 2010 | 941.752990722656 | Thousand metric tons | 28.13% |
| 2011 | 966 | Thousand metric tons | 2.57% |
| 2012 | 1000 | Thousand metric tons | 3.52% |
| 2013 | 1000 | Thousand metric tons | 0.00% |
