distribute	reads
0-500	153492
500-800	87276
800-1000	69010
1000-1200	124426
1200-1400	225277
1400-1600	293022
1600-1800	297356
1800-2000	277834
2000-2200	247989
2200-2400	216215
2400-2600	187825
2600-2800	162526
2800-3000	141222
>3000	1319098
