distribute	reads
0-500	0
500-800	0
800-1000	0
1000-1200	0
1200-1400	1
1400-1600	2
1600-1800	4
1800-2000	6
2000-2200	14
2200-2400	21
2400-2600	62
2600-2800	101
2800-3000	214
>3000	18899
