A typical final salary scheme will pay a pension that depends on:
The accrual rate is the proportion of your final salary you get for each year you are a member of the scheme. Accrual rates are usually expressed as fractions (1/60 or 1/80 is common) or sometimes as a percentage (which would make 1/60 the same as 1.67 per cent)
It's probably easier to see with an example.
Lucy retires with a salary of £30,000 after being a scheme member for twenty years. Her scheme has a 1/60 accrual rate. Her pension will be worked out this way.
For every year she worked she will get 1/60 of £30,000. This is £500 for each year. So for twenty years' service her first year's pension will be £10,000.
The accrual rate is an important part of how good a salary related scheme is. The commonest rate now is probably about 1/80th, although many schemes have cut accrual rates in recent years. Very good schemes will do better with 1/60th or even 1/50th.
Poorer schemes may go as low as 1/100th. Of course, more generous schemes will cost more, and employee contributions may be higher than in a poorer scheme.