distribute	reads
0-500	0
500-800	1
800-1000	1
1000-1200	1
1200-1400	7
1400-1600	6
1600-1800	2
1800-2000	12
2000-2200	26
2200-2400	66
2400-2600	89
2600-2800	179
2800-3000	296
>3000	22722
