distribute	reads
0-500	1
500-800	0
800-1000	0
1000-1200	0
1200-1400	0
1400-1600	0
1600-1800	0
1800-2000	0
2000-2200	1
2200-2400	1
2400-2600	4
2600-2800	7
2800-3000	8
>3000	308
