distribute	reads
0-500	377569
500-800	239368
800-1000	106025
1000-1200	82746
1200-1400	67779
1400-1600	57062
1600-1800	49116
1800-2000	43738
2000-2200	39101
2200-2400	35654
2400-2600	32595
2600-2800	29923
2800-3000	28057
>3000	587853
