distribute	reads
0-500	307882
500-800	23051
800-1000	1300
1000-1200	240
1200-1400	52
1400-1600	15
1600-1800	6
1800-2000	0
2000-2200	0
2200-2400	0
2400-2600	0
2600-2800	0
2800-3000	0
>3000	0
