create macro variable from data field

[Kurt_Bremser]

What is the size of your person key?

Your observation size would be determined by person key + date + county code, so I assume something like 10 + 4 (SAS dates can be stored in 4 bytes) + 6, giving 20 bytes. So you get 720 * 20 million bytes, or ~ 15 GB, which is really not large for today's computing power.