S.D. Codified Laws § 62-4-7
In case of total disability as defined in subdivision 62-4-6(23), compensation shall be paid at the rate provided by § 62-4-3 for life with an annual increase in the amount of the benefit allowance for each year commencing on the July first that is at least twelve months following the date on which the benefit was first payable equal to one hundred percent of the annual percentage change in the consumer price index for urban wage earners and clerical workers as computed by the United States Department of Labor for the prior calendar year, not to exceed a three percent increase compounded annually.
For injuries occurring on or after July 1, 1993, if an employee is entitled to compensation under this section and is also receiving old-age insurance benefits under section 202 of the Social Security Act (42 U.S.C., § 402), the compensation payable shall be a sum equal to one hundred fifty percent of the compensation payable under § 62-4-7 less the old-age insurance benefit under § 202 of the Social Security Act (42 U.S.C., § 402). However, benefits payable by the employer may not exceed the amount payable pursuant to § 62-4-7. This section does not apply to any person who is entitled to old-age insurance benefits at the time of the injury.
SDCL 62-4-7