distribute	reads
0-500	408906
500-800	202960
800-1000	81563
1000-1200	60892
1200-1400	48050
1400-1600	39717
1600-1800	33384
1800-2000	28866
2000-2200	25244
2200-2400	22684
2400-2600	20216
2600-2800	18466
2800-3000	17002
>3000	353340
