distribute	reads
0-500	26616
500-800	21877
800-1000	14041
1000-1200	13289
1200-1400	12511
1400-1600	12107
1600-1800	11199
1800-2000	10523
2000-2200	10030
2200-2400	9555
2400-2600	9015
2600-2800	8473
2800-3000	7778
>3000	110661
