You would have a compute block, something like:
The only complication is that the internal length of the BU variable must be big enough to hold the string "Total'. There are ways around it if BU is numeric or a length of 2 -- but the simple compute block above should work if the BU variable is character length of at least 5.
ps...also, please do me a favor and move your OPTIONS statement outside of your PROC REPORT step. It just bothers me to see the OPTIONS statement in the wrong place.