| 0% | No symptoms. No symptoms following physical or mental exertion. Normal overall activity level. Able to work full time without difficulty. |
| 10% | No symptoms at rest. Mild symptoms following physical or mental exertion. Normal overall activity level. Able to work full time without difficulty. |
| 20% | Mild symptoms at rest, worsened by physical or mental exertion. Minimal activity restriction noted for activities requiring exertion only. Able to work full time with difficulty in jobs requiring exertion. |
| 30% | Mild symptoms at rest. Daily activity limitation clearly noted; overall functioning 70% to 90% of expected, except for activities requiring exertion. Able to work full time with difficulty. |
| 40% | Mild to moderate symptoms at rest. Daily activity limitation clearly noted; overall functioning 70% to 90% of expected. Unable to work full time in jobs requiring physical labour, but able to work full time in light activity if hours flexible. |
| 50% | Moderate symptoms at rest. Moderate to severe symptoms following physical or mental exertion; overall activity level reduced to 70% of expected. Unable to perform strenuous duties, but able to perform light duty or desk work 4-5 hours a day, but requires rest periods. |
| 60% | Moderate symptoms at rest. Moderate to severe symptoms following any physical or mental exertion; overall activity level reduced to 50% to 70% of expected. Not confined to the house. Unable to perform strenuous duties. Able to perform light duty or desk work 3-4 hours a day, but requires rest periods. |
| 70% | Moderate to severe symptoms at rest. Severe symptoms following any physical or mental exertion; overall activity level reduced to 50% of expected. Usually confined to the house. Unable to perform any strenuous tasks. Able to perform desk work 2-3 hours a day, but requires rest periods. |
| 80% | Moderate to severe symptoms at rest. Unable to perform strenuous activity; overall activity 30% to 50% of expected. Unable to leave the house except rarely. confined to bed most of the day. Unable to concentrate for more than one hour a day. |
| 90% | Severe symptoms at rest. Bed-ridden the majority of time. No travel outside the house. Marked cognitive symptoms prevent concentration. |
| 100% | Severe symptoms on a continuous basis. Bed-ridden constantly. Unable to care for yourself. |