Actually, the wording is a bit tricky. The quote I found was "Retiring with $5 million dollars is an exceptionally rare achievement. According to data from the Employee Benefit Research Institute, based on the
Federal Reserve’s Survey of Consumer Finances, a mere 0.1% of retirees have managed to accumulate over $5 million in their retirement accounts. This statistic underscores the exclusivity of such high-value retirements."
However, "Retiring with $5M" is NOT the same thing as having "$5M in their retirement accounts." Still, whether you only consider retirement-specific accounts, or all investible assets, $5M is a pretty exclusive club!
Most of the figures I've seen thrown around indicates that $5M puts you roughly in the top 1%, but that's total net worth, not just investible assets. And I've seen some figures recently, putting $13.6M as the new threshold for the top 1%! So I guess the real answer is that it's like trying to figure out how many licks it takes to get to the Tootsie Roll center of a Tootsie Pop. The world may never know!