Thank you Pavithran.
I have tried a range of things and only by converting a lead does the number seem to change. Adding new leads for that same month does not seem to decrease the percentage as would be expected. Adding new leads and changing their status to 'closed' or 'qualified out' does not change the percentage either (I was testing here whether it was converted leads (divided by) all leads x100 or whether it was converted leads (divided by) ('actioned' leads i.e. qualified out+qualified in) x100).
I was wondering whether there was a way to view the calculation as I have tried and tested a few different scenarios to see how the numbers would change but it doesn't seem to be behaving as expected.
Thanks,
Anouska