According to August 2012 data by the Employee Benefits Research Institute, all age groups saw an uptick in their 401(k) retirement  account balances in the past month.

Those ages 25 to 34, with one to four years of savings under their belt, saw a 3.2 percent increase in their account balances in August. Those with five to nine years of savings saw a 2.6 percent increase in their account balances.

Older age groups didn’t experience quite the growth in account balances as the 25- to 34-year-old age group, with those 35 to 44 experiencing a 2.9 percent increase with one to four years of tenure; a 2.4 percent increase for five to nine years of tenure and 2.2 percent for 10 to 19 years of tenure.

For those ages 45 to 54, the range of increase went from 1.8 percent in the 20 to 29-year tenure range to 2.5 percent for the one to four-year tenure range.

For individuals ages 55 to 64, they saw account balance increases of 1.6 percent to 2.1 percent, depending on tenure.

These projections are based on all participants who had account balances at the end of 2010 and contribution information for that year.