Employers sponsoring 401(k) plans are worried about employees’ retirement readiness even as account balances hit all-time highs, according to a new survey from Deloitte.

Only 12% of plan sponsors feel that most of their employees are or will be financially prepared for retirement, down from 15% who felt so a year ago. The vast majority of sponsors (70%) feel that only some of their employees will be prepared.

The lack of confidence comes despite increased account balances averaging $85,000, a record, according to the 12th annual 401(k) benchmarking survey.

“Despite the encouraging data regarding the increase in 401(k) balances and educational tools offered, more still needs to be done to help employees adequately prepare for their individual retirement needs,” Scott Cole, senior manager of Human Capital at Deloitte Consulting, said in a statement.

To increase employees’ retirement preparedness, plan sponsors have enhanced their 401(k) participant education strategies, the survey found. For example, 32% reported conducting retirement readiness assessments for employees, up from 25% in 2011. And more began offering employees individual financial counseling and advice, with 61% offering the additional service.

The online survey canvassed nearly 400 plan sponsors from August to November of 2012. It was conducted by Deloitte, the International Foundation of Employee Benefit Plans and the International Society of Certified Employee Benefit Specialists.