distribute	reads
0-500	149432
500-800	108838
800-1000	81047
1000-1200	111097
1200-1400	181318
1400-1600	255475
1600-1800	292637
1800-2000	287248
2000-2200	262786
2200-2400	233025
2400-2600	209365
2600-2800	187796
2800-3000	170018
>3000	1762445
