Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 15.3000001907349 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 44.9000015258789 | Thousand metric tons of contained nitrogen | 193.46 % |
| 2005 | 45 | Thousand metric tons of contained nitrogen | 0.22 % |
| 2006 | 35 | Thousand metric tons of contained nitrogen | -22.22 % |
| 2007 | 25 | Thousand metric tons of contained nitrogen | -28.57 % |
| 2008 | 25 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2009 | 20 | Thousand metric tons of contained nitrogen | -20.00 % |
