distribute	reads
0-500	9442
500-800	4828
800-1000	1496
1000-1200	910
1200-1400	508
1400-1600	311
1600-1800	168
1800-2000	84
2000-2200	58
2200-2400	31
2400-2600	27
2600-2800	13
2800-3000	6
>3000	21
