Difficult to reply without the actual data, but this works, if that's what you want:
[pre]
data t;
CUS=1; ARREARS=1; INS=3; output;
CUS=1; ARREARS=1; INS=1; output;
CUS=2; ARREARS=1; INS=0; output;
run;
option nocenter formchar='|========================';
proc tabulate;
class CUS;
var ARREARS INS;
table CUS, ARREARS*sum INS*sum ARREARS*pctsum
='Rate';
run;
===============================================================
| | ARREARS | INS | ARREARS |
| ========================================
| | Sum | Sum | Rate |
===============================================================
|CUS | | | |
======================== | | |
|1 | 2.00| 4.00| 50.00|
===============================================================
|2 | 1.00| 0.00| .|
===============================================================