"[T]he data and projections presented include the Trustees' best estimates of the effects of the COVID-19 pandemic and the 2020 recession ... [T]he finances of both programs have been significantly affected, as employment, earnings, interest rates and GDP dropped substantially in the second quarter of 2020. And while these economic indicators are presumed to rise gradually toward full recovery by 2023, the level of worker productivity and GDP assumed are projected to be permanently lowered by 1%[.]"