44 (Expressed in Trinidad and Tobago Dollars) NOTES TO THE SPECIAL PURPOSE FINANCIAL STATEMENTS 30th June 2017 4 Summary of significant accounting policies (continued) l. Revenue recognition (i) Contribution and benefits Contribution income is generally accounted for on the cash basis. An accrual is made at the balance sheet date to take account of all collections up to 15 July of the following year that relate to the current year. Contribution arrears and related penalty and interest are recognised when received as a result of uncertainty in collection and the challenge in estimating and determining contributors in default. Benefit expenditure is generally accounted for on a cash basis. Benefits paid in the final month of the year which relate to the following year are reflected as a prepayment at the statement of financial position date. (ii) Investment income Income from investments is accounted for on the accrual basis. Interest from commercial loans and debentures is not accrued where instalments are in arrears for more than twelve months. m. Employee benefits (i) Short term Employee benefits are all forms of consideration given by NIBTT in exchange for service rendered by its employees. These include current or short-term benefits such as salaries, bonuses, NIS contributions, annual leave, and non-monetary benefits such as medical care and loans; post-employment benefits such as pensions; and other long-term employee benefits such as termination benefits. Employee benefits that are earned as a result of past or current service are recognised in the following manner: short-term employee benefits are recognised as a liability, net of payments made, and charged as expense. Post-employment benefits are accounted for as described below. (ii) Post employment NIBTT contributes to a defined benefit staff pension plan which covers all qualifying employees. Members contribute 5% (2016: 5%) of their pensionable salaries to the Plan whilst NIBTT currently contributes 14% (2016: 14%). All permanent employees are eligible for membership and temporary employees under certain conditions. The liability recognised in the statement of financial position in respect of defined benefit pension plan is the present value of the defined benefit obligation at the end of the reporting period less the fair value of plan assets. The defined benefit obligation is calculated annually by independent actuaries using the projected unit credit method. The present value of the defined benefit obligation is determined by discounting the estimated future cash outflows using interest rates of high-quality corporate bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity approximating to the terms of the related pension obligation. In countries where there is no deep market in such bonds, the market rates on the government bonds are used. Actuarial gains and losses arising from experience adjustments and changes in actuarial assumptions are charged or credited to equity in other comprehensive income in the period in which the arise. Past-service costs are recognised immediately in income.