This depends how the vendors have implemented supply level reporting on the SNMP protocol.

Printers report supply levels in different increment levels.

Some examples from different printers:

1) 100%, 75%, 50%, 25% and 0%

2) Enough, 50%, 25% and 0%

3) 100%, 10% and 0%

4) 100%, 80%, 60%, 40%, 20% and 0%

5) 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and 0%

6) 100%, 99%, 98%, 97%,,,,,,,,,,,,, 6%, 5%, 4%, 3%, 2%, 1% and 0%

7) 100%, 99%, 98%, 97%,,,,,,,,,,,,, 21% and 20% (or even higher levels as the last level in some cases)

8) Enough and 0%

To check how a printer reports supply level, goto the printer details page (click the grey/blue icon left to the printer name)

Select the "Supplies" tab and click on a supply under "Supply History" and here you can see which algorithm the printer uses for the supply levels.