proc sort data = seria3.L06z06_a sortseq=linguistic(Numeric_Collation=ON) out = Z6s1;
    by i;
run;

data z6s;
    set z6s1;
    by i;
    if first.i then k=k+1;
    retain k 0;
run;

proc sort data = z6s sortseq=ascii out = z6 (drop = k);
    by k descending j;
run;