U.S. retirement assets rose 1 percent to $20.9 trillion in the second quarter of 2013, according to the Investment Company Institute.

The data encompasses assets held in IRAs, defined contribution and defined benefit plans, government plans and annuity reserves.

At the end of June, retirement savings accounted for 34 percent of all household financial assets in the United States.

Assets in individual retirement accounts totaled $5.7 trillion at the end of the second quarter of 2013, an increase of 0.9 percent from the end of the first quarter. Defined contribution plan assets rose 1 percent in the second quarter to $5.3 trillion, with $3.8 trillion of that in 401(k) plans.

Those figures are relatively unchanged from $5.3 trillion and $3.7 trillion, respectively, as of March 31, 2013. Mutual funds managed $3.1 trillion, or 58 percent, of assets held in 401(k), 403(b), and other DC plans at the end of June.

Government pension plans — including federal, state, and local government plans — held $5.2 trillion in assets as of the end of June, a 1.4 percent increase from the end of March. Private-sector defined benefit plans held $2.8 trillion in assets at the end of the second quarter of 2013, and annuity reserves outside of retirement accounts accounted for another $1.8 trillion.

As of June 30, target date mutual fund assets totaled $540 billion, an increase of 2.1 percent in the second quarter. Retirement accounts held the bulk of target date mutual fund assets: 90 percent of target date mutual fund assets were held through DC plans and IRAs.