distribute	reads
0-500	6998
500-800	5452
800-1000	4786
1000-1200	5947
1200-1400	8045
1400-1600	11877
1600-1800	17821
1800-2000	25326
2000-2200	34874
2200-2400	43662
2400-2600	51493
2600-2800	55207
2800-3000	55895
>3000	253205
