Why today's grads won't retire until they're 75

Here's another financial headache for young adults as they graduate from college and prepare to enter the workforce.

Even though one recent survey shows that a large percentage of Americans are willing to delay retirement to help their children or grandchildren pay for college, another report now suggests that those new, millennial-generation graduates probably won't be able to retire until they're around age 75. Blame rising rental costs and the soaring rate of student loan debt.

Those findings from NerdWallet are based on a typical 23-year-old college graduate who has the average $35,000 in education debt -- an all-time high -- and is earning a median starting salary of around $45,500 a year.

"The student loan crisis is not only affecting new graduates' immediate financial situation, it's making their retirement prospects dwindle," said Kyle Ramsay, investing manager at NerdWallet. "Based on our findings, higher loan payments have the potential to reduce nest eggs by 32 percent. That's nearly $700,000 in this scenario."

Adding to the problem, rent prices are expected to climb for the next several years. The NerdWallet report quotes research from Zillow showing rents have risen 11 percent nationally over the past three years. For new graduates, that means the money they could have put into savings will instead end up paying for rent.

Even the millennials who do manage to save, Ramsay told CBS MoneyWatch, are leaving too much of their money sitting in cash or low-interest saving accounts. "Having seen the turbulence of the 2009 financial crisis and the impact it had on many people's parents and their retirements, many distrust markets," he noted.

No investment strategy is without risk, he acknowledged, but millennials have the advantage of time and can probably take on a bit more financial risk in the decades ahead of their retirement years.

Ramsay pointed to lower-risk alternatives to stocks, such as Treasury Inflation Protected bonds (TIPs). However, he added, "because bonds have lower expected return than stocks, one would need to have a much higher savings rate in order to achieve retirement savings goals using fixed-income investments only."

The NerdWallet report also suggests that a new graduate consider living at home for a while after getting out of school. The company calculates that millennials who live at home until age 25 could end up retiring at age 70, rather than 75.