The overall ratio of transfer will be much less than 1:1.
No matter how many full nodes you have on the network, each of them has to download every new block. This means that the number of blocks downloaded divided by the number of nodes has to be at least 1.
It could be higher if some nodes download the same block from more than 1 node.
This is separate from the initial download. Some storage nodes are needed for bootstrapping.
Sorry I misinterpreted the discussion.... -- the OP was referring to transfer of the entire block chain so I didn't realize it had abstracted from that to discussion on new blocks with the initial block chain being separate. I had meant unless 5000(or more specifically, equivalent to however many nodes there are) new nodes were added, there wouldn't be a 1:1 ratio of transfer of the entire block chain.