distribute	reads
0-500	4666
500-800	6859
800-1000	4054
1000-1200	3733
1200-1400	3179
1400-1600	2927
1600-1800	2633
1800-2000	2334
2000-2200	2177
2200-2400	2030
2400-2600	1848
2600-2800	1778
2800-3000	1612
>3000	21984
