Historical data indicated that the time required to service the conveyor belt at Coca-Cola Amatil's Richlands operations can be modelled as a normal distribution with a standard deviation of 22 minutes. A random sample of 18 services revealed a mean service duration of 82.9 minutes. Determine a 99% confidence interval for the mean service time in minutes. State the upper bound of this interval (in minutes) correct to two decimal places.