distribute	reads
0-500	1
500-800	0
800-1000	0
1000-1200	0
1200-1400	1
1400-1600	7
1600-1800	8
1800-2000	11
2000-2200	9
2200-2400	11
2400-2600	4
2600-2800	4
2800-3000	1
>3000	0
