distribute	reads
0-500	7
500-800	4
800-1000	0
1000-1200	2
1200-1400	1
1400-1600	1
1600-1800	2
1800-2000	3
2000-2200	2
2200-2400	4
2400-2600	1
2600-2800	4
2800-3000	3
>3000	222
