(i) General rule.— If the beneficiary (other than a dependent child) is 62 years of age or older when becoming entitled to the annuity, the monthly annuity shall be the amount equal to the product of the base amount and the percent applicable to the month, as follows:
(I) For a month before October 2005, the applicable percent is 35 percent.
(II) For months after September 2005 and before April 2006, the applicable percent is 40 percent.
(III) For months after March 2006 and before April 2007, the applicable percent is 45 percent.
(IV) For months after March 2007 and before April 2008, the applicable percent is 50 percent.
(V) For months after March 2008, the applicable percent is 55 percent.