Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 53 | Thousand metric tons | NA |
| 2004 | 59 | Thousand metric tons | 11.32 % |
| 2005 | 62.1319999694824 | Thousand metric tons | 5.31 % |
| 2006 | 62.9480018615723 | Thousand metric tons | 1.31 % |
| 2007 | 63 | Thousand metric tons | 0.08 % |
| 2008 | 82.5189971923828 | Thousand metric tons | 30.98 % |
| 2009 | 115.727996826172 | Thousand metric tons | 40.24 % |
