distribute	reads
0-500	88
500-800	42
800-1000	21
1000-1200	17
1200-1400	18
1400-1600	12
1600-1800	9
1800-2000	1
2000-2200	5
2200-2400	6
2400-2600	1
2600-2800	3
2800-3000	0
>3000	2
