distribute	reads
0-500	2
500-800	0
800-1000	0
1000-1200	0
1200-1400	0
1400-1600	0
1600-1800	0
1800-2000	0
2000-2200	0
2200-2400	0
2400-2600	1
2600-2800	1
2800-3000	3
>3000	17
