Use non-blank values only

I want to calculate the percentage of a column. Normally the formula I would use is this:

Percentage = 
DIVIDE('QC Total Table'[Linear KM], 
SUM('QC Total Table'[Linear KM]))

However, I want to only calculate the percentage of a column if there is a value (not blank rows) in another column. 

QC %GT Complete = 
IF('QC Total Table'[QC Artist] <> BLANK(), 
	DIVIDE('QC Total Table'[Linear KM], 
		SUM('QC Total Table'[Linear KM])))

In the table, it looks correct. Only shows % values for non blank rows, but I am still not getting a correct result out of 100%, it is still including the blank rows somehow.

Thank you for your help