Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1388.69995117188 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1379.5 | Thousand metric tons of contained nitrogen | -0.66% |
| 2005 | 1380 | Thousand metric tons of contained nitrogen | 0.04% |
| 2006 | 1250 | Thousand metric tons of contained nitrogen | -9.42% |
| 2007 | 1300 | Thousand metric tons of contained nitrogen | 4.00% |
| 2008 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2010 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2011 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2012 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
