PERCENTAGEIFS

PERCENTAGEIFS(rgeValues, sCondition, iDecimalPlaces)
Returns the percentage of numbers in a range that satisfy multiple conditions.

rgeValues	The range of values.
sCondition	The condition you want to use.
iDecimalPlaces	The number of decimal places you want the percentage returned as.

REMARKS
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Public Function PERCENTAGEIFS( _ 
         ByVal rgeValues As Range, _ 
         ByVal sCondition As String, _ 
         ByVal iDecimalPlaces As Integer) _ 
         As Double 

   PERCENTAGEIFS = VBA.Round((Application.WorksheetFunction.CountIf(rgeValues, sCondition) / _ 
                 Application.WorksheetFunction.Count(rgeValues)) * 100, iDecimalPlaces) 

End Function

For instructions on how to add this function to a workbook refer to the page under Inserting Functions