Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 58.2999992370605 | Metric tons | NA |
| 2004 | 70.7300033569336 | Metric tons | 21.32% |
| 2005 | 92.5 | Metric tons | 30.78% |
| 2006 | 108.900001525879 | Metric tons | 17.73% |
| 2007 | 116.5 | Metric tons | 6.98% |
| 2008 | 82.5400009155273 | Metric tons | -29.15% |
| 2009 | 83 | Metric tons | 0.56% |
