distribute	reads
0-500	74426
500-800	53368
800-1000	26194
1000-1200	20957
1200-1400	16984
1400-1600	14007
1600-1800	11691
1800-2000	9938
2000-2200	8216
2200-2400	6979
2400-2600	5983
2600-2800	5150
2800-3000	4458
>3000	33562
