distribute	reads
0-500	214
500-800	906
800-1000	794
1000-1200	947
1200-1400	1047
1400-1600	1167
1600-1800	1093
1800-2000	1056
2000-2200	1012
2200-2400	962
2400-2600	936
2600-2800	862
2800-3000	777
>3000	12459
