Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 938.799987792969 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1077.40002441406 | Thousand metric tons of contained nitrogen | 14.76% |
| 2005 | 950 | Thousand metric tons of contained nitrogen | -11.82% |
| 2006 | 950 | Thousand metric tons of contained nitrogen | 0.00% |
| 2007 | 950 | Thousand metric tons of contained nitrogen | 0.00% |
| 2008 | 950 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 950 | Thousand metric tons of contained nitrogen | 0.00% |
