Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2002 | 69271 | Kilograms | NA |
| 2003 | 70749 | Kilograms | 2.13% |
| 2004 | 63139 | Kilograms | -10.76% |
| 2005 | 66852 | Kilograms | 5.88% |
| 2006 | 69817 | Kilograms | 4.44% |
| 2007 | 83558 | Kilograms | 19.68% |
| 2008 | 73819 | Kilograms | -11.66% |
| 2009 | 67818 | Kilograms | -8.13% |
| 2010 | 72441 | Kilograms | 6.82% |
| 2011 | 82919 | Kilograms | 14.46% |
| 2012 | 86540 | Kilograms | 4.37% |
