distribute	reads
0-500	53828
500-800	33755
800-1000	19344
1000-1200	17151
1200-1400	15666
1400-1600	14319
1600-1800	12509
1800-2000	11356
2000-2200	10262
2200-2400	9257
2400-2600	8399
2600-2800	7725
2800-3000	7040
>3000	84650
