The unfunded liability amount was the amount of a levy imposed upon each local authority employer by the fund in October 1997 to meet the then accrued unfunded liabilities of the fund. Circular 12/97 dated 20 October 1997 issued by the trustee, which was in evidence before the magistrate, not only notified the Shire that the ongoing contribution rate for its employees would be reduced from 13.25% to 9.25% of their salaries, effective from 1 July 1997, but also provided that in respect of each authority an unfunded liability amount determined by the trustee had to be paid by 30 June 2007. The total unfunded liability of the fund was said to be $321M which was apportioned between the various local government authorities whose employees were members of the fund. Each such authority was required to make minimum annual instalment payments in diminution of its apportioned liability such that the total amount of such liability, together with contributions tax applicable, would be paid by 30 June 2007 - ten years from the date of the imposition of the levy. Such instalment payments in respect of the LASF's unfunded liabilities were and are not referable to any particular employee, whether past or present. They are simply overheads which the Shire must meet as a consequence of conducting its operations in much the same way as it must meet its other business liabilities such as the cost of light, power, rent or fuel. Although the fact that the Shire had to meet such instalment payments was in evidence before the magistrate it was not suggested that that fact in any way affected the proper construction of Mr Strong's employment contract. The evidence was apparently lead, although of very doubtful relevance, as an explanation as to why the Shire's liability to make ongoing superannuation payments was reduced from 13.25% to 9.25% of employees' salaries.