distribute	reads
0-500	0
500-800	66
800-1000	34
1000-1200	13
1200-1400	7
1400-1600	10
1600-1800	11
1800-2000	13
2000-2200	4
2200-2400	13
2400-2600	1
2600-2800	6
2800-3000	4
>3000	53
