Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 125 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 130 | Thousand metric tons of contained nitrogen | 4.00% |
| 2005 | 130 | Thousand metric tons of contained nitrogen | 0.00% |
| 2006 | 140 | Thousand metric tons of contained nitrogen | 7.69% |
| 2007 | 150 | Thousand metric tons of contained nitrogen | 7.14% |
| 2008 | 150 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 150 | Thousand metric tons of contained nitrogen | 0.00% |
| 2010 | 150 | Thousand metric tons of contained nitrogen | 0.00% |
| 2011 | 145 | Thousand metric tons of contained nitrogen | -3.33% |
| 2012 | 150 | Thousand metric tons of contained nitrogen | 3.45% |
