distribute	reads
0-500	0
500-800	0
800-1000	2
1000-1200	2
1200-1400	2
1400-1600	4
1600-1800	5
1800-2000	8
2000-2200	8
2200-2400	3
2400-2600	14
2600-2800	24
2800-3000	21
>3000	397
