distribute	reads
0-500	0
500-800	42
800-1000	23
1000-1200	12
1200-1400	9
1400-1600	6
1600-1800	4
1800-2000	7
2000-2200	7
2200-2400	8
2400-2600	4
2600-2800	4
2800-3000	8
>3000	92
