distribute	reads
0-500	0
500-800	34
800-1000	9
1000-1200	8
1200-1400	3
1400-1600	2
1600-1800	1
1800-2000	2
2000-2200	1
2200-2400	0
2400-2600	0
2600-2800	0
2800-3000	0
>3000	0
