distribute	reads
0-500	79554
500-800	12402
800-1000	6300
1000-1200	7013
1200-1400	8391
1400-1600	10601
1600-1800	15053
1800-2000	21731
2000-2200	31535
2200-2400	42747
2400-2600	55893
2600-2800	67810
2800-3000	79892
>3000	1300553
