Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 32711 | Metric tons | NA |
| 2003 | 26275 | Metric tons | -19.68 % |
| 2004 | 103153 | Metric tons | 292.59 % |
| 2005 | 133325 | Metric tons | 29.25 % |
| 2006 | 147836 | Metric tons | 10.88 % |
| 2007 | 205728 | Metric tons | 39.16 % |
| 2008 | 206000 | Metric tons | 0.13 % |
