awk 'BEGIN { AMIN=99999999; AMAX=-AMIN; BMIN=AMIN; BMAX=AMAX; OFS="\t"; BINSIZE=10; }

{        A=sprintf("%d", $2/BINSIZE);
          B=sprintf("%d", $3/BINSIZE);
          if(A<AMIN) AMIN=A; else if(A>AMAX) AMAX=A;
          if(B<BMIN) BMIN=B; else if(B>BMAX) BMAX=B;
          BIN[A,B]++;
}
END { for(A=AMIN; A<=AMAX; A++)
         for(B=BMIN; B<=BMAX; B++)
         print A*BINSIZE, B*BINSIZE, BIN[A,B]; }' inputfile