"That said, voluntary choice is still important, with nearly half of single target-date investors choosing the funds on their own, not through default," the report said.
Two-thirds of Vanguard plan participants who own target-date funds have their entire accounted invested in a single target-date fund, the report said.
“Our research ... has shown plan sponsors have a continued commitment to improving plan design for participants, which has led to positive results -- increased participation, savings rates, and improved portfolio construction," Martha King, managing director of Vanguard’s Institutional Investor Group, said in a prepared statement. "Moreover, the greater adoption of target-date funds signals a shift in responsibility as participants’ investment decision-making is increasingly moving toward employer-selected investment and advice programs.”