Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1759 | Metric tons | NA |
| 2004 | 1880 | Metric tons | 6.88% |
| 2005 | 1727 | Metric tons | -8.14% |
| 2006 | 2090 | Metric tons | 21.02% |
| 2007 | 1388 | Metric tons | -33.59% |
| 2008 | 1409 | Metric tons | 1.51% |
| 2009 | 1299 | Metric tons | -7.81% |
| 2010 | 1357 | Metric tons | 4.46% |
| 2011 | 1240 | Metric tons | -8.62% |
| 2012 | 1286 | Metric tons | 3.71% |
| 2013 | 1400 | Metric tons | 8.86% |
