distribute	reads
0-500	563
500-800	2267
800-1000	1799
1000-1200	2204
1200-1400	2830
1400-1600	3169
1600-1800	3017
1800-2000	2934
2000-2200	2916
2200-2400	2843
2400-2600	2714
2600-2800	2522
2800-3000	2406
>3000	42508
