distribute	reads
0-500	505819
500-800	28415
800-1000	1766
1000-1200	367
1200-1400	73
1400-1600	29
1600-1800	8
1800-2000	1
2000-2200	3
2200-2400	1
2400-2600	0
2600-2800	0
2800-3000	1
>3000	6
