Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 112 | Thousand metric tons | NA |
| 2004 | 100 | Thousand metric tons | -10.71% |
| 2005 | 2860.01806640625 | Thousand metric tons | 2,760.02% |
| 2006 | 3002.72705078125 | Thousand metric tons | 4.99% |
| 2007 | 2958.05908203125 | Thousand metric tons | -1.49% |
| 2008 | 3160.22607421875 | Thousand metric tons | 6.83% |
| 2009 | 2241.31494140625 | Thousand metric tons | -29.08% |
| 2010 | 267 | Thousand metric tons | -88.09% |
| 2011 | 312 | Thousand metric tons | 16.85% |
| 2012 | 257 | Thousand metric tons | -17.63% |
| 2013 | 260 | Thousand metric tons | 1.17% |
