distribute	reads
0-500	147088
500-800	89593
800-1000	44732
1000-1200	38243
1200-1400	33409
1400-1600	30390
1600-1800	27413
1800-2000	24453
2000-2200	22196
2200-2400	20369
2400-2600	18515
2600-2800	17043
2800-3000	15360
>3000	185279
