Set up a number field with a check box format. Use a custom value list with just one value, the number 1. Put this field on your layout with the check box format, but size the field so narrow that only the check box is visible.
Then Year 2 can be set up like this:
If ( checkboxFieldHere ; YourCalculationHere )
The field will only show a calculated result if the check box is selected.
Worked like a charm. Thanks for the assist.