A member shall receive a service retirement annuity, payable semi-monthly, and computed as follows:
Tier I Formula:
The average of the 5 (five) highest salaries in the last 10 (ten) years multiplied by the applicable retirement factor as provided in the table below and multiplied by the number of years of credited service equal the estimated annual annuity.
Tier II Formula:
The average of the career salaries multiplied by the applicable retirement factor as provided in the table below and multiplied by the number of years of credited service equals the estimated annual annuity.
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If the member is under age 60 and has less than 30 years of service, the annual annuity is reduced by .325 for each month the member is under age 60.