distribute	reads
0-500	21071
500-800	11327
800-1000	5789
1000-1200	5003
1200-1400	4233
1400-1600	3464
1600-1800	3196
1800-2000	2809
2000-2200	2453
2200-2400	2217
2400-2600	1877
2600-2800	1785
2800-3000	1551
>3000	15989
