To see what a typical American actually has saved, the median balance (the exact midpoint of all accounts) paints a very different picture.
For example, while Vanguard's average is $167,970, their median balance is only $44,115. Furthermore, because of expanded automatic enrollment over the past decade, a flood of new, younger workers have entered plans with $0 balances, keeping the true median account growth relatively flat over the 10-year span.
The best metric for tracking true 10-year growth is looking at individuals who have steadily contributed to the same account without stopping. According to Fidelity's data, workers who have saved continuously for the last 10 straight years boast an average balance of $501,800.