Number format based on value of the number

Hi

I have a worksheet with a very simple table, showing events and number of occurrences of each event.  I have then changed the number of occurrences to percent of total.  I have amended the number format so that the percentage is to 0 decimal places.  However, one minor tweak I would like to make, if possible, is where the percentage is less than 1% is to have the figure formatted to one decimal place (to indicate if it is a low number or a zero).  Is that possible?

Thanks very much

Philip