| 0... | Agriculture, Forestry, Fisheries |
| 1... | Mining and Construction |
| 2... | Manufacturing |
| 4... | Transportation, Communications and Other Public Utilities |
| 5... | Wholesale and Retail Trade |
| 6... | Finance, Insurance and Real Estate |
| 7... | Services |
| 9... | Public Administration, Government, Law, Justice, Security |
| 9999 | Nonclassifiable Establishments |
| ???? | Unclassified Establishments |