distribute	reads
0-500	3716
500-800	2811
800-1000	1297
1000-1200	1094
1200-1400	904
1400-1600	852
1600-1800	1047
1800-2000	1249
2000-2200	2883
2200-2400	3118
2400-2600	3360
2600-2800	3441
2800-3000	3452
>3000	23226
