Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 170 | Thousand metric tons | NA |
| 2004 | 237 | Thousand metric tons | 39.41% |
| 2005 | 224 | Thousand metric tons | -5.49% |
| 2006 | 179 | Thousand metric tons | -20.09% |
| 2007 | 140.74299621582 | Thousand metric tons | -21.37% |
| 2008 | 172.259002685547 | Thousand metric tons | 22.39% |
| 2009 | 284 | Thousand metric tons | 64.87% |
| 2010 | 296 | Thousand metric tons | 4.23% |
| 2011 | 352 | Thousand metric tons | 18.92% |
| 2012 | 260 | Thousand metric tons | -26.14% |
| 2013 | 429 | Thousand metric tons | 65.00% |
