distribute	reads
0-500	65
500-800	2
800-1000	0
1000-1200	1
1200-1400	3
1400-1600	1
1600-1800	2
1800-2000	3
2000-2200	3
2200-2400	2
2400-2600	5
2600-2800	6
2800-3000	12
>3000	44
