distribute	reads
0-500	43445
500-800	43300
800-1000	11658
1000-1200	6735
1200-1400	4323
1400-1600	2974
1600-1800	2183
1800-2000	1757
2000-2200	1406
2200-2400	1270
2400-2600	1094
2600-2800	940
2800-3000	886
>3000	19091
