aged...years old

[Unregistered]

Please could you advise which of the following is correct:

The main users of ****(company name) were people aged 35-59, who accounted for 55% of all clients undergoing treatment.

The main users of ****(company name) were people aged 35-59 years, who accounted for 55% of all clients undergoing treatment.

The main users of ****(company name) were people aged 35-59 years old, who accounted for 55% of all clients undergoing treatment.

Many thanks

[IvanV]

Please could you advise which of the following is correct:

The main users of ****(company name) were people aged 35-59, who accounted for 55% of all clients undergoing treatment.

The main users of ****(company name) were people aged 35-59 years, who accounted for 55% of all clients undergoing treatment.

The main users of ****(company name) were people aged 35-59 years old, who accounted for 55% of all clients undergoing treatment.

Many thanks

I.