help required on developing a formula

Hi,

I need help with creating a formula that calculates success rate (percentage of successful projects vs all) in the Success rate percentage tab of the attached file based on the True/false date in the project list tab (column L). Can you help?

Hello
In order to devise a formula, I need to understand the points at which the calculation is needed. You say it is based on column L, which suggests one percentage based on the proportion of cells in the column that evaluate to TRUE. However, that doesn't explain all the date headers in the SCP sheet, so I gather that you have forgotten to describe how they fit in.
Can you add a couple of examples of the percentage calculation?