Why with the increase in the number of users, the average throughput has increased？

[hy zhao]

I simulated the average throughput of users in a multiuser LTE scenario， TCP connection between users and server. 

When I make the wireless bandwidth 25RBs ，I found that the  average throughput  of two users is larger that of one user. 

I don't konw why, I think the average throughput will decrease with  the increasing of users.