Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 450 | Thousand metric tons | NA |
| 2003 | 450 | Thousand metric tons | 0.00% |
| 2004 | 641 | Thousand metric tons | 42.44% |
| 2005 | 713 | Thousand metric tons | 11.23% |
| 2006 | 2101 | Thousand metric tons | 194.67% |
| 2007 | 2100 | Thousand metric tons | -0.05% |
| 2008 | 2300 | Thousand metric tons | 9.52% |
| 2009 | 2000 | Thousand metric tons | -13.04% |
| 2010 | 2100 | Thousand metric tons | 5.00% |
| 2011 | 2239 | Thousand metric tons | 6.62% |
| 2012 | 2351 | Thousand metric tons | 5.00% |
| 2013 | 2400 | Thousand metric tons | 2.08% |
