(c) Definitions related to determination of rates of tax
(1) Average account benefits ratio
For purposes of this section, the term average account benefits ratio means, with respect to any calendar year, the average determined by the Secretary of the account benefits ratios for the 10 most recent fiscal years ending before such calendar year. If the amount determined under the preceding sentence is not a multiple of 0.1, such amount shall be increased to the next highest multiple of 0.1.
(2) Account benefits ratio
For purposes of this section, the term account benefits ratio means, with respect to any fiscal year, the amount determined by the Railroad Retirement Board by dividing the fair market value of the assets in the Railroad Retirement Account and of the National Railroad Retirement Investment Trust (and for years before 2002, the Social Security Equivalent Benefits Account) as of the close of such fiscal year by the total benefits and administrative expenses paid from the Railroad Retirement Account and the National Railroad Retirement Investment Trust during such fiscal year.