It's a dumb question, but can anyone tell me how many inches off the surface of the desk are the ports on the back of the iMac (height between where iMac sits and the i/o ports)? For example, lets the say the length of the height between the chin of the iMac and the desk was 4 inches, what is the length of the height between the back ports of the iMac and surface of the desk? I would appreciate if anyone could help me with this important question. Thanks so much.