distribute	reads
0-500	426671
500-800	223371
800-1000	94775
1000-1200	72112
1200-1400	57623
1400-1600	48277
1600-1800	41311
1800-2000	36398
2000-2200	32969
2200-2400	29846
2400-2600	28147
2600-2800	26366
2800-3000	24706
>3000	932693
