Source: United States Geological Survey (USGS) Minerals Resources Program
Note: Check source table for details and footnotes
| Year | Production | Unit of Measure | % Change |
| 2003 | 1180.09997558594 | Thousand metric tons of contained nitrogen | NA |
| 2004 | 1182 | Thousand metric tons of contained nitrogen | 0.16% |
| 2005 | 1300 | Thousand metric tons of contained nitrogen | 9.98% |
| 2006 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2007 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2008 | 1300 | Thousand metric tons of contained nitrogen | 0.00% |
| 2009 | 40 | Thousand metric tons of contained nitrogen | -96.92% |
| 2010 | 80 | Thousand metric tons of contained nitrogen | 100.00% |
| 2011 | 160 | Thousand metric tons of contained nitrogen | 100.00% |
| 2012 | 115 | Thousand metric tons of contained nitrogen | -28.13% |
