distribute	reads
0-500	197129
500-800	61897
800-1000	23915
1000-1200	17122
1200-1400	12945
1400-1600	10137
1600-1800	8173
1800-2000	6857
2000-2200	5847
2200-2400	5012
2400-2600	4490
2600-2800	4052
2800-3000	3579
>3000	54695
