distribute	reads
0-500	572588
500-800	787670
800-1000	319410
1000-1200	229002
1200-1400	172877
1400-1600	135388
1600-1800	110290
1800-2000	90501
2000-2200	76923
2200-2400	65494
2400-2600	56877
2600-2800	49486
2800-3000	44092
>3000	455178
