24. From time to time the Scheme was modified to introduce various "plans" each with a separate benefit structure. In 1982 the Principal Employer decided to establish the C Plan which would offer better benefits than the N Plan although unlike the N Plan, which was non-contributory, members would be required to contribute a proportion of their earnings. Under C Plan rules, normal retirement date was the member's 63rd birthday and pensions accrued at a rate which would entitle members to receive a pension of two-thirds their final pensionable earnings in 38 years, ie an accrual rate of approximately I/50ths. There was no provision for guaranteed increases to pensions in payment. In the same year the A Plan was established to receive Additional Voluntary Contributions (AVCs). Another AVC plan, the T Plan, which Mr Mitchell joined, and which is a money purchase plan, was added in 1988.