distribute	reads
0-500	28838
500-800	28196
800-1000	14927
1000-1200	11890
1200-1400	8834
1400-1600	6367
1600-1800	4372
1800-2000	2972
2000-2200	1779
2200-2400	1152
2400-2600	668
2600-2800	417
2800-3000	230
>3000	367
