distribute	reads
0-500	1518
500-800	4976
800-1000	4470
1000-1200	4680
1200-1400	4410
1400-1600	3893
1600-1800	3237
1800-2000	2627
2000-2200	1942
2200-2400	1453
2400-2600	1059
2600-2800	799
2800-3000	556
>3000	1117
