distribute	reads
0-500	35088
500-800	34733
800-1000	17964
1000-1200	14893
1200-1400	12645
1400-1600	10572
1600-1800	9153
1800-2000	7680
2000-2200	6797
2200-2400	5649
2400-2600	5047
2600-2800	4384
2800-3000	3840
>3000	31559
