%mktkey(5 10)

%mktkey(5 10 t)

%mktkey(x1-x15)

data key;
   input (x1-x5) ($);
   datalines;
 x1  x2  x3  x4  x5
 x6  x7  x8  x9 x10
x11 x12 x13 x14 x15
  .   .   .   .   .
;