distribute	reads
0-500	0
500-800	1
800-1000	0
1000-1200	0
1200-1400	2
1400-1600	0
1600-1800	3
1800-2000	0
2000-2200	2
2200-2400	5
2400-2600	13
2600-2800	29
2800-3000	39
>3000	8561
