Member: Marketing Constituent Cost Per Piece

CREATE MEMBER CURRENTCUBE.[Measures].[Marketing Constituent Cost Per Piece]
 AS IIF
(
  [Measures].[Marketing Constituent Count] > 0,
  [Measures].[Marketing Constituent Total Cost] / [Measures].[Marketing Constituent Count]
  ,null
), 
FORMAT_STRING = "Currency", 
VISIBLE = 1 ,  ASSOCIATED_MEASURE_GROUP = 'Marketing Constituent';