Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1044 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1071.09997558594 | Thousand metric tons of contained nitrogen | 2.60% |
| 2005 | 1080 | Thousand metric tons of contained nitrogen | 0.83% |
| 2006 | 750 | Thousand metric tons of contained nitrogen | -30.56% |
| 2007 | 1050 | Thousand metric tons of contained nitrogen | 40.00% |
| 2008 | 1100 | Thousand metric tons of contained nitrogen | 4.76% |
| 2009 | 1100 | Thousand metric tons of contained nitrogen | 0.00% |
| 2010 | 1100 | Thousand metric tons of contained nitrogen | 0.00% |
| 2011 | 1100 | Thousand metric tons of contained nitrogen | 0.00% |
| 2012 | 1100 | Thousand metric tons of contained nitrogen | 0.00% |
