distribute	reads
0-500	0
500-800	27
800-1000	12
1000-1200	6
1200-1400	5
1400-1600	5
1600-1800	1
1800-2000	1
2000-2200	1
2200-2400	2
2400-2600	0
2600-2800	2
2800-3000	1
>3000	9
