A quastion about "passenger demand"

[Guiiido]

Hy....
I notice that some routes (for example Venice-Cairo) has a "Passenger demand" of 500 per day and the return fly (Cairo-Venice in this case) has "Passenger demand" of only 150 per day...
It isnt strange?
Usually if someone go somewhere he also come back. But how this passenger do that?
Thank u and sorry for my english

[JonesyUK]

https://www.airwaysim.com/forum/index.php/topic,7254.0.html 

[Guiiido]

Thank u very much!!!
I didn't find anything about...but i think i didn't search well! ;