distribute	reads
0-500	180
500-800	556
800-1000	2224
1000-1200	8169
1200-1400	23110
1400-1600	50672
1600-1800	81380
1800-2000	94468
2000-2200	85222
2200-2400	68985
2400-2600	53945
2600-2800	40620
2800-3000	26616
>3000	24577
