(a) Estimates of annual appropriations
The Director shall prepare the estimates of the annual appropriations required to be made to the fund.

(b) Actuarial valuations
The Director shall cause to be made actuarial valuations of the fund at such intervals as the Director determines to be necessary, but not less often than every five years.

(c) Changes in law affecting actuarial status of fund
Any statute which authorizes—

(1) new or increased benefits payable from the fund under this subchapter, including annuity increases other than under section 2131 of this title;

(2) extension of the coverage of this subchapter to new groups of employees; or

(3) increases in pay on which benefits are computed;

is deemed to authorize appropriations to the fund in order to provide funding for the unfunded liability created by that statute, in 30 equal annual installments with interest computed at the rate used in the then most recent valuation of the system and with the first payment thereof due as of the end of the fiscal year in which such new or liberalized benefit, extension of coverage, or increase in pay is effective.

(d) Authorization
There is hereby authorized to be appropriated to the fund for each fiscal year such amounts as may be necessary to meet the amount of normal cost for each year that is not met by contributions under section 2021(a) of this title.

(e) Unfunded liability; credit allowed for military service
There is hereby authorized to be appropriated to the fund for each fiscal year such sums as may be necessary to provide the amount equivalent to—

(1) interest on the unfunded liability computed for that year at the interest rate used in the then most recent valuation of the system; and

(2) that portion of disbursement for annuities for that year that the Director estimates is attributable to credit allowed for military service,

less an amount determined by the Director to be appropriate to reflect the value of the deposits made to the credit of the fund under section 2082(h) of this title.