First, Happpy retirement!. Your agent at the Insurance Company has an obligation to tell you what the inflation rate is!.
Second, the Insurance Company should furnish you with an "amortization schedule". From that you should be able to see the increase in your retirement payments by dividing the 2nd year's payment by the 1st year's payment.
Third, there is a specific, rather complicated formula, to figure out the inflation rate. I suspect that that is the formula the computer used to figure out your initial annual payment of $35,838.50. I happened to know the formula, which is programmed in my computer. I plugged in all your numbers and the computer came up with the rate of exactly 2.5% per year. This means that your first payment of $35,838.50 already includes 2.50% inflation rate. Your initial payment will increase by 2.5% each and every year for 30 years, so that your last payment would be:$35,838.50/1.025 x 1.025^30=$73,340.17.
Good luck and happy and healthy retirement years. If you want any clarification, just let us know here.