distribute	reads
0-500	52083
500-800	41232
800-1000	26123
1000-1200	24947
1200-1400	23040
1400-1600	22113
1600-1800	20027
1800-2000	18888
2000-2200	17934
2200-2400	16539
2400-2600	15314
2600-2800	14365
2800-3000	13196
>3000	173741
