Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 21324 | Kilograms | NA |
| 2003 | 20406 | Kilograms | -4.31% |
| 2004 | 21818 | Kilograms | 6.92% |
| 2005 | 30356 | Kilograms | 39.13% |
| 2006 | 38961 | Kilograms | 28.35% |
| 2007 | 39355 | Kilograms | 1.01% |
| 2008 | 50365 | Kilograms | 27.98% |
| 2009 | 51393 | Kilograms | 2.04% |
| 2010 | 72596 | Kilograms | 41.26% |
| 2011 | 84118 | Kilograms | 15.87% |
| 2012 | 96650 | Kilograms | 14.90% |
