distribute	reads
0-500	742665
500-800	33022
800-1000	2179
1000-1200	489
1200-1400	83
1400-1600	19
1600-1800	7
1800-2000	3
2000-2200	1
2200-2400	2
2400-2600	0
2600-2800	1
2800-3000	0
>3000	12
