distribute	reads
0-500	7
500-800	1
800-1000	0
1000-1200	1
1200-1400	2
1400-1600	0
1600-1800	1
1800-2000	1
2000-2200	2
2200-2400	0
2400-2600	3
2600-2800	3
2800-3000	5
>3000	180
