distribute	reads
0-500	96226
500-800	50201
800-1000	19757
1000-1200	13695
1200-1400	9985
1400-1600	7535
1600-1800	5734
1800-2000	4469
2000-2200	3564
2200-2400	3143
2400-2600	2694
2600-2800	2315
2800-3000	2018
>3000	28935
