distribute	reads
0-500	387144
500-800	137095
800-1000	53112
1000-1200	38989
1200-1400	29917
1400-1600	24544
1600-1800	20334
1800-2000	17065
2000-2200	14453
2200-2400	12526
2400-2600	10852
2600-2800	9774
2800-3000	8493
>3000	81652
