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