distribute	reads
0-500	37910
500-800	53305
800-1000	23311
1000-1200	15833
1200-1400	10953
1400-1600	7468
1600-1800	5087
1800-2000	3589
2000-2200	2200
2200-2400	1473
2400-2600	954
2600-2800	583
2800-3000	357
>3000	542
