distribute	reads
0-500	14397
500-800	43691
800-1000	25684
1000-1200	19214
1200-1400	13723
1400-1600	9375
1600-1800	6096
1800-2000	4000
2000-2200	2504
2200-2400	1631
2400-2600	1057
2600-2800	692
2800-3000	431
>3000	728
