distribute	reads
0-500	0
500-800	59
800-1000	13
1000-1200	11
1200-1400	3
1400-1600	8
1600-1800	4
1800-2000	1
2000-2200	1
2200-2400	1
2400-2600	2
2600-2800	4
2800-3000	1
>3000	15
