Annual Report 2017

151 For the years ended 31 December 2017 and 2016, the principal actuarial assumptions used were as follows: Expected maturity analysis of undiscounted retirement and other benefits: 2017 2016 Discount rate as of 31 December 2.75% 3.60% Salary increase rate - permanent employees 6.5% 5.00% - 10.00% Salary increase rate - contract employees 6.5% 4.50% Average turnover rate 0.00% - 13.00% 0.00% - 13.00% Pre-retirement mortality rate 75% of TMO2017 TMO2008 Retirement age 60 years old 60 years old Impact on defined benefit obligation Change in assumption Increase in assumption Decrease in assumption 2017 2016 2017 2016 2017 2016 Discount rate 1 % 1 % Decrease by 12% Decrease by 11% Increase by 13% Increase by 13% Salary growth rate 1 % 1 % Increase by 14% Increase by 15% Decrease by 12% Decrease by 13% Turnover growth rate 20 % 20 % Decrease by 5% Decrease by 8% Increase by 6% Increase by 9% The above sensitivity analyses are based on a change in an assumption while holding all other assumptions constant. In practice, this is unlikely to occur, and changes in some of the assumptions may be correlated. When calculating the sensitivity of the defined benefit obligation to significant actuarial assumptions the same method (present value of the defined benefit obligation calculated with the projected unit credit method at the end of the reporting period) has been applied as when calculating the pension liability recognised within the statement of financial position. The methods and types of assumptions used in preparing the sensitivity analysis did not change compared to the previous period. The weighted average duration of the defined benefit obligation is 20 years (2016: 22 years). Consolidated Within a year 1-5 years Over 5 years Total At 31 December 2017 Retirement benefits 5,970 34,249 508,512 548,731 Other benefits 2,484 11,288 20,038 33,810 Total 8,454 45,537 528,550 582,541 (Unit: Baht’000)