CPI Date

[mcarr5]

I am looking for a formula which would return a CPI review date on a lease data base.
Each lease is reviewed every 3rd year for increase according to the CPI Index. We abated this review due to the economic conditions for years 2009,2010&2011. If your lease had a cpi date in those years, I need to capture that fact and identify the year.
I think a simple math formula would work but I've racked my brain to no avail. The worksheet attached shows the array. Any help appreciated.
Mike