distribute	reads
0-500	136
500-800	297
800-1000	486
1000-1200	1053
1200-1400	1875
1400-1600	2734
1600-1800	3327
1800-2000	3436
2000-2200	3609
2200-2400	3314
2400-2600	3206
2600-2800	3087
2800-3000	2867
>3000	74941
