Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 56 | Thousand metric tons | NA |
| 2003 | 50 | Thousand metric tons | -10.71% |
| 2004 | 60 | Thousand metric tons | 20.00% |
| 2005 | 60 | Thousand metric tons | 0.00% |
| 2006 | 60 | Thousand metric tons | 0.00% |
| 2007 | 60 | Thousand metric tons | 0.00% |
| 2008 | 60 | Thousand metric tons | 0.00% |
| 2009 | 254.154006958008 | Thousand metric tons | 323.59% |
| 2010 | 395.462005615234 | Thousand metric tons | 55.60% |
| 2011 | 1254.09997558594 | Thousand metric tons | 217.12% |
| 2012 | 1911.30004882813 | Thousand metric tons | 52.40% |
| 2013 | 2785.13305664063 | Thousand metric tons | 45.72% |
