When to deduct State Sales Tax Collected for Business?

My business collects state sales tax and pays Annually, ex. 03/01/2018 - 02/28/19.

So for 2018 income tax return (schedule C) do we use the amount paid in 2018 on the 2018 State sales tax return, which was for 03/01/2017 - 02/28/2018? or do we use the actual amount collected in 2018 and deduct that?

 

Thank you!