distribute	reads
0-500	759
500-800	3114
800-1000	2779
1000-1200	3707
1200-1400	4259
1400-1600	4504
1600-1800	4572
1800-2000	4370
2000-2200	4444
2200-2400	4106
2400-2600	4046
2600-2800	3760
2800-3000	3684
>3000	53543
