How can I turn a formula like:

=COUNTIF('Person 1'!$C8,"Off")+COUNTIF('Person 2'!$C8,"Off")+COUNTIF('Person
3'!$C8,"Off")+COUNTIF('Person 4'!$C8,"Off")+COUNTIF('Person 5'!$C8,"Off")

Into (something like):

=COUNTIF('Person 1':'Person 5'!$C8,"Off") ... this gives #NAME?
=COUNTIF('Person 1:Person 5'!$C8,"Off") ... this gives #VALUE!

It doesn't have to be the COUNTIF function so long as it achieves the same
ends.

I need to be able to add more people without a vast amount of repetition.
It would look neater and simpler too!

Thanks in advance

Trevor