The Interest rates over the next 4 years will vary as follows: For the first 1.5 years, the annual effective rate of interest is 7%. For the subsequent year, the annual interest rate compounded quarterly is 8%. For the subsequent 1.5 years, the annual interest rate compounded monthly is 6%. A deposit is made now will be accumulated over the next 4 years. Calculate the equivalent level interest rate earned over the 4 years, expressed as a nominal annual interest rate compounded semiannually