Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 9770 | Kilograms | NA |
| 2003 | 9300 | Kilograms | -4.81% |
| 2004 | 10151 | Kilograms | 9.15% |
| 2005 | 10583 | Kilograms | 4.26% |
| 2006 | 10618 | Kilograms | 0.33% |
| 2007 | 10638 | Kilograms | 0.19% |
| 2008 | 13402 | Kilograms | 25.98% |
| 2009 | 13442 | Kilograms | 0.30% |
| 2010 | 13494 | Kilograms | 0.39% |
| 2011 | 14324 | Kilograms | 6.15% |
| 2012 | 10164 | Kilograms | -29.04% |
