Recalculating Rents Based On CPI ?

[mdsnj]

Hi,

I recently realized that I was paying too much of a rent increase. I would like to recalculate the last 2 years rent increase based on the Consumers Price Index, as stated in my lease.

My question is, do I calculate the next year's CPI based on my newly calculated CPI result of the previous year? Or, do I calculate the next year's CPI based on what I actually paid to my landlord the previous year?

Any help would be greatly appreciated.
Thank you.