tier 2 dependant form

hi,
i am on tier 2 general.i was filling form for my spouse. I wonder what number they want us to write in 7.15?
certificate of sponsership number ? Can someone advice please?

Ref: PBS Dependant Guidance Notes.

"7.15 What is the main applicant’s Certificate of Sponsorship
or Confirmation of Acceptance for Studies number?
(Tier 2 and Tier 5 (Temporary Worker) and Tier 4 only, otherwise
leave blank)
For applicants in Tier 2, 4 and Tier 5 (Temporary Worker), this is
the number allocated to the main applicant by his/her employer/
prospective employer/educational establishment. He/she is required
to enter the number on their entry clearance application form and
would not/will not have been issued entry clearance without doing
so. Please leave blank for Tier 4 applicants who applied using a
visa letter.".