Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 577 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 577 | Thousand metric tons of contained nitrogen | 0.00% |
| 2005 | 507 | Thousand metric tons of contained nitrogen | -12.13% |
| 2006 | 518 | Thousand metric tons of contained nitrogen | 2.17% |
| 2007 | 523 | Thousand metric tons of contained nitrogen | 0.97% |
| 2008 | 417 | Thousand metric tons of contained nitrogen | -20.27% |
| 2009 | 530 | Thousand metric tons of contained nitrogen | 27.10% |
| 2010 | 580 | Thousand metric tons of contained nitrogen | 9.43% |
| 2011 | 71 | Thousand metric tons of contained nitrogen | -87.76% |
| 2012 | 79 | Thousand metric tons of contained nitrogen | 11.27% |
