zero and blank values

Hi Team.

good day. im working on Goal Attainment per metric. and my goal is to calculate the percentage of each metric on how close they are to the Goals. im having troubles with this formula: Transfer GA = if([Transfers]=BLANK(),BLANK(),IF([Transfers]=0,1,if([Transfers]<=.05,1,0))) the result that i want to show is if its 0% transfer rate, then the GA should be 100% and if its blank, or null. it should show blank. but since BI reads blank and 0 the same, i dont know what fomula should use. please see screen shot below.