Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 40 | Thousand metric tons | NA |
| 2003 | 40 | Thousand metric tons | 0.00 % |
| 2004 | 50 | Thousand metric tons | 25.00 % |
| 2005 | 50 | Thousand metric tons | 0.00 % |
| 2006 | 130 | Thousand metric tons | 160.00 % |
| 2007 | 207 | Thousand metric tons | 59.23 % |
| 2008 | 250 | Thousand metric tons | 20.77 % |
| 2009 | 333 | Thousand metric tons | 33.20 % |
| 2010 | 418 | Thousand metric tons | 25.53 % |
| 2011 | 400 | Thousand metric tons | -4.31 % |
| 2012 | 380 | Thousand metric tons | -5.00 % |
