Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 16967 | Metric tons | NA |
| 2004 | 24353 | Metric tons | 43.53% |
| 2005 | 24882 | Metric tons | 2.17% |
| 2006 | 24645 | Metric tons | -0.95% |
| 2007 | 32912 | Metric tons | 33.54% |
| 2008 | 30504 | Metric tons | -7.32% |
| 2009 | 16042 | Metric tons | -47.41% |
| 2010 | 314 | Metric tons | -98.04% |
| 2013 | 18808 | Metric tons | 5,889.81% |
