Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 440 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 440 | Thousand metric tons of contained nitrogen | 0.00% |
| 2005 | 440 | Thousand metric tons of contained nitrogen | 0.00% |
| 2006 | 440 | Thousand metric tons of contained nitrogen | 0.00% |
| 2007 | 440 | Thousand metric tons of contained nitrogen | 0.00% |
| 2008 | 400 | Thousand metric tons of contained nitrogen | -9.09% |
| 2009 | 370 | Thousand metric tons of contained nitrogen | -7.50% |
| 2010 | 400 | Thousand metric tons of contained nitrogen | 8.11% |
| 2011 | 400 | Thousand metric tons of contained nitrogen | 0.00% |
| 2012 | 400 | Thousand metric tons of contained nitrogen | 0.00% |
