distribute	reads
0-500	56643
500-800	31861
800-1000	18364
1000-1200	16737
1200-1400	15563
1400-1600	14320
1600-1800	12778
1800-2000	11971
2000-2200	11030
2200-2400	10320
2400-2600	9732
2600-2800	9104
2800-3000	8477
>3000	147460
