The increase in assets held by individuals in Roth IRAs grew at twice the rate of assets in traditional IRAs from 2010 to 2012, according to data released by the Employee Benefit Research Institute (EBRI) Wednesday.

The EBRI IRA Database measured the balances of Roth and traditional IRAs held by individuals in the three years studied.

The median increase in assets for owners of Roth IRAs was 16.6 percent during the three years, compared to an increase of 7.9 percent for owners of traditional IRAs. EBRI also found that Roth IRA balances grew faster than traditional IRAs at each age group and for both genders.

Looking at individuals who maintained an IRA account over the three-year period, the average balance increased each year—from $95,431 in 2010 to $95,547 in 2011 and to $106,205 in 2012, EBRI says.

The EBRI IRA Database tracks individual IRA owners with more than one account across multiple providers. At the end of 2012, it contained information on 25.3 million accounts owned by 19.9 million individuals, representing total assets of $2.09 trillion.

The EBRI database represents a portion of the total $6 trillion in IRA assets. In the EBRI database, 82 percent of the assets are in traditional IRAs and 8 percent in Roth IRAs.

The full report, Individual Retirement Account Balances, Contributions, and Rollovers, 2012; With Longitudinal Results 2010–2012: The EBRI IRA Database, is published in the May 2014 EBRI Issue Brief at www.ebri.org