Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 2077 | Metric tons | NA |
| 2003 | 1868 | Metric tons | -10.06% |
| 2004 | 2224 | Metric tons | 19.06% |
| 2005 | 2417 | Metric tons | 8.68% |
| 2006 | 1727 | Metric tons | -28.55% |
| 2007 | 1879 | Metric tons | 8.80% |
| 2008 | 1926 | Metric tons | 2.50% |
| 2009 | 1635 | Metric tons | -15.11% |
| 2010 | 1864 | Metric tons | 14.01% |
| 2011 | 1725 | Metric tons | -7.46% |
| 2012 | 1728 | Metric tons | 0.17% |
