"Overall, the average account balance increased at a compound annual average growth rate of 19.4 percent from 2016 to 2020, rising from $78,008 to $158,361 at year-end 2020.... Younger 401(k) participants or those with smaller year-end 2016 balances experienced higher percent growth in account balances compared with older participants or those with larger year-end 2016 balances.... On average at year-end 2020, more than two-thirds of consistent 401(k) participants' assets were invested in equities[.]"