Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 75000 | Metric tons | NA |
| 2004 | 80000 | Metric tons | 6.67% |
| 2005 | 104500 | Metric tons | 30.63% |
| 2006 | 124000 | Metric tons | 18.66% |
| 2007 | 137000 | Metric tons | 10.48% |
| 2008 | 135000 | Metric tons | -1.46% |
| 2009 | 140000 | Metric tons | 3.70% |
| 2009 | 93000 | Metric tons | -33.57% |
| 2010 | 100000 | Metric tons | 7.53% |
| 2011 | 100000 | Metric tons | 0.00% |
| 2012 | 105000 | Metric tons | 5.00% |
| 2013 | 110000 | Metric tons | 4.76% |
