Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 200 | Thousand metric tons | NA |
| 2003 | 200 | Thousand metric tons | 0.00% |
| 2004 | 300 | Thousand metric tons | 50.00% |
| 2005 | 300 | Thousand metric tons | 0.00% |
| 2006 | 373.963012695313 | Thousand metric tons | 24.65% |
| 2007 | 409.513000488281 | Thousand metric tons | 9.51% |
| 2008 | 322 | Thousand metric tons | -21.37% |
| 2009 | 324 | Thousand metric tons | 0.62% |
| 2010 | 552 | Thousand metric tons | 70.37% |
| 2011 | 565 | Thousand metric tons | 2.36% |
| 2012 | 570 | Thousand metric tons | 0.88% |
