distribute	reads
0-500	3368
500-800	17
800-1000	11
1000-1200	7
1200-1400	5
1400-1600	4
1600-1800	3
1800-2000	1
2000-2200	3
2200-2400	1
2400-2600	3
2600-2800	1
2800-3000	2
>3000	6
