Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 909.5 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 842.5 | Thousand metric tons of contained nitrogen | -7.37% |
| 2005 | 920 | Thousand metric tons of contained nitrogen | 9.20% |
| 2006 | 950 | Thousand metric tons of contained nitrogen | 3.26% |
| 2007 | 960 | Thousand metric tons of contained nitrogen | 1.05% |
| 2008 | 950 | Thousand metric tons of contained nitrogen | -1.04% |
| 2009 | 950 | Thousand metric tons of contained nitrogen | 0.00% |
