distribute	reads
0-500	12977
500-800	6640
800-1000	4738
1000-1200	5827
1200-1400	8274
1400-1600	13020
1600-1800	20104
1800-2000	30683
2000-2200	43575
2200-2400	57061
2400-2600	70016
2600-2800	80093
2800-3000	84221
>3000	580540
