distribute	reads
0-500	10612
500-800	15339
800-1000	18635
1000-1200	28166
1200-1400	37104
1400-1600	40181
1600-1800	36811
1800-2000	28097
2000-2200	19804
2200-2400	13295
2400-2600	8700
2600-2800	5109
2800-3000	2852
>3000	4643
