Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 90000 | Metric tons | NA |
| 2004 | 90000 | Metric tons | 0.00% |
| 2005 | 70000 | Metric tons | -22.22% |
| 2006 | 72000 | Metric tons | 2.86% |
| 2007 | 79000 | Metric tons | 9.72% |
| 2008 | 70000 | Metric tons | -11.39% |
| 2009 | 44000 | Metric tons | -37.14% |
| 2010 | 96000 | Metric tons | 118.18% |
| 2011 | 147000 | Metric tons | 53.13% |
| 2012 | 154000 | Metric tons | 4.76% |
| 2013 | 175000 | Metric tons | 13.64% |
