distribute	reads
0-500	50301
500-800	31409
800-1000	18177
1000-1200	16622
1200-1400	15399
1400-1600	14175
1600-1800	12962
1800-2000	11994
2000-2200	11207
2200-2400	10914
2400-2600	9972
2600-2800	9468
2800-3000	8368
>3000	144087
