Numbering cells while skipping cells that already have contents

[bmv505]

I have a spreadsheet that is tracking the number of plays in a football drive. I code the individual stat entries by action. So there is drive start = “Drive”, kickoff = “KO”, timeout= “TO”, etc. The actual plays are numbered by what play they are in the drive, so “Drive” restarts the counting. However, I want to skip over the non-offensive entries such as a penalty that results in a “NO Play.” Is there a formula or function that would allow me to do this to a whole sheet without going through and manually entering the number?

 

[bmv505]

Still looking for help. Thank you in advance