distribute	reads
0-500	7743
500-800	7412
800-1000	5597
1000-1200	6477
1200-1400	8016
1400-1600	10000
1600-1800	12547
1800-2000	15646
2000-2200	19419
2200-2400	22688
2400-2600	24325
2600-2800	23774
2800-3000	21107
>3000	87437
