distribute	reads
0-500	6026
500-800	9171
800-1000	3541
1000-1200	2817
1200-1400	2242
1400-1600	1928
1600-1800	1829
1800-2000	1743
2000-2200	1729
2200-2400	1736
2400-2600	1661
2600-2800	1623
2800-3000	1646
>3000	28893
