distribute	reads
0-500	127090
500-800	89158
800-1000	44725
1000-1200	36671
1200-1400	30960
1400-1600	27245
1600-1800	24248
1800-2000	21738
2000-2200	20162
2200-2400	18331
2400-2600	16915
2600-2800	15884
2800-3000	14920
>3000	425503
