| Thetford - Occupational Data | FIPS Code=17055 |
| 1970 | |
| Employed Population | 534 |
| Professional - Technical - Kindred | 92 |
| Non-Farm Manager - Administrator | 58 |
| Sales Worker | 17 |
| Clerical Worker | 54 |
| Craftsperson - Foreperson | 43 |
| Non-Transport Operative | 35 |
| Transport Operative | 40 |
| Non-Farm Laborer | 33 |
| Farmer - Farm Manager | 19 |
| Farm Laborer | 21 |
| Non-Private Service | 22 |
| Household Service | 32 |
| Occupation Not Reported | 68 |
| 1980 | 1990 | |
| Employed Population | 1025 | 1354 |
| Executive - Administrator | 95 | 157 |
| Professional Speciality | 205 | 391 |
| Technicians - Related Support | 35 | 53 |
| Sales | 59 | 61 |
| Administrative - Clerical | 147 | 168 |
| Private Household Service | 8 | 2 |
| Protective Service | 8 | 0 |
| Non-Household, Non-Protective Service | 106 | 124 |
| Natural Resources | 51 | 118 |
| Precision Production - Craft | 166 | 181 |
| Machine Operators | 43 | 27 |
| Mover | 65 | 58 |
| Labor | 37 | 14 |
| 1980 | 1990 | ||
| Per Cent of Working Population Employed in Town of Residence | 18.90 | 27.40 | |
| 1970 | 1980 | 1990 | |
| Unemployment Rate | 1.87 | 2.66 | 5.05 |