Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1185.30004882813 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1428 | Thousand metric tons of contained nitrogen | 20.48 % |
| 2005 | 1753.98400878906 | Thousand metric tons of contained nitrogen | 22.83 % |
| 2006 | 1784 | Thousand metric tons of contained nitrogen | 1.71 % |
| 2007 | 1800 | Thousand metric tons of contained nitrogen | 0.90 % |
| 2008 | 1800 | Thousand metric tons of contained nitrogen | 0.00 % |
| 2009 | 1800 | Thousand metric tons of contained nitrogen | 0.00 % |
