Calculate the percentage of dates within specific time periods?

Hi All,

Basically what I have is a spreadsheet which contains training modules down the left hand side, and employee names across the top. Once an employee has been trained in a particular module, the corresponding field has a date entered into it which states when the next training date is.

I have conditionally formatted this to warn the user when the refresher training is going to be required.

So
Cell values greater than TODAY()+120 then it's green, the training date is far
Cell values between TODAY()+30 and TODAY()+120 is yellow, meaning it's drawing closer
Cell values between TODAY() and TODAY()+30 is pink, meaning it's very close
Cell values less than TODAY() are red indicating training is overdue

This has been formatted to several sheets for different departments

Now what I want to achieve is a new sheet where I can extract the following information and this is the part I need help with:
- I need the percentage of dates within each of the above criteria for monitoring purposes: i.e. what percentage of training is green, yellow, pink and red
How do I do this and what formula would I need to use?


Thanks in advance