distribute	reads
0-500	0
500-800	30
800-1000	10
1000-1200	6
1200-1400	7
1400-1600	3
1600-1800	1
1800-2000	2
2000-2200	0
2200-2400	1
2400-2600	0
2600-2800	1
2800-3000	1
>3000	9
