distribute	reads
0-500	21298
500-800	7908
800-1000	4999
1000-1200	5950
1200-1400	8125
1400-1600	12723
1600-1800	20692
1800-2000	33980
2000-2200	51524
2200-2400	73427
2400-2600	97764
2600-2800	120903
2800-3000	138859
>3000	1069534
