Virtual Processors to Physical

Hi:

We have (10) Physical Hyper-V hosts running Server 2012 DataCenter.  Each Host has 2 Sockets, 12 Cores and therefore 24 Logical Processors.

When I look in VMM 2012 Sp1, I show that we are using right now 182 cores and that is spread out over 100 VM's.  Can someone help me understand how many more cores we should have left to assign and/or what the ratio/calculation is for best practice here?

Thank you,
Stangride