distribute	reads
0-500	167670
500-800	4017
800-1000	181
1000-1200	51
1200-1400	25
1400-1600	6
1600-1800	4
1800-2000	2
2000-2200	0
2200-2400	2
2400-2600	0
2600-2800	0
2800-3000	1
>3000	1
