distribute	reads
0-500	48954
500-800	23603
800-1000	10843
1000-1200	8767
1200-1400	7027
1400-1600	5825
1600-1800	4707
1800-2000	3966
2000-2200	3374
2200-2400	2927
2400-2600	2517
2600-2800	2171
2800-3000	1923
>3000	17516
