distribute	reads
0-500	0
500-800	25
800-1000	4
1000-1200	5
1200-1400	4
1400-1600	2
1600-1800	3
1800-2000	0
2000-2200	0
2200-2400	2
2400-2600	0
2600-2800	0
2800-3000	1
>3000	3
