Section 1767.71 - Periods of retention(a) Records of Rural Development borrowers of a kind not listed in the FERC regulations should be governed by those applicable to the closest similar records. Financial requirement and expenditure statements, which are not specifically covered by FERC regulations, are recommended to be kept for one year after the "as of date" of Rural Development's loan fund and accounting review.(b) Consumer accounts' records should be kept for those years for which patronage capital has not been allocated.(c) Records supporting construction financed by Rural Development shall be retained until audited and approved by Rural Development.(d) Records related to plant in service must be retained until the facilities are permanently removed from utility service, all removal and restoration activities are completed, and all costs are retired from the accounting records unless accounting adjustments resulting from reclassification and original costs studies have been approved by Rural Development or other regulatory body having jurisdiction.(e) Life and mortality study data for depreciation purposes must be retained for 25 years or for 10 years after plant is retired, whichever is longer.