Peter borrowed a sum of R12 850.00 at the beginning of a year with a certain simple interest rate. After 14 quarters, in a different loan, he borrowed an extra sum of R3 273.00, but at the simple interest half the former. At the end of four years, Peter paid a simple interest amount of R1 980.00 for both the loans. The original annual simple interest rate, rounded to two decimal places, is?​