The HHS awarding agency or pass-through entity must require a non-Federal entity to submit reports at least annually on the status of real property in which the Federal Government retains an interest, unless the Federal interest in the real property extends 15 years or longer. In those instances where the Federal interest attached is for a period of 15 years or more, the HHS awarding agency or pass-through entity, at its option, may require the non-Federal entity to report at various multi-year frequencies (e.g., every two years or every three years, not to exceed a five-year reporting period; or an HHS awarding agency or pass-through entity may require annual reporting for the first three years of a Federal award and thereafter require reporting every five years).