Zip Code missing in Bill To: area of Invoice template

Zip Code missing in Bill To: area of Invoice template

I have worked hard to customized a modern invoice template and just discovered that the customer's Zip code is missing from the Bill To area. What is the code for that? 

I only have:

%CustomerBAddress%
%CustomerBCity%, %CustomerBState% [zip code needs to go here]

Thanks,
-Ian