When it comes to retirement savings, many Americans seem to be "winging it" -- or heading for retirement without a realistic plan of how to fund it.

Or so suggests a recent survey by the Transamerica Center for Retirement Studies. The survey indicates that "retirement planning" is a very loose concept among Americans. In many cases, the approach could be better described as wishful thinking.

The following are some points of concern raised by the study:

The median contribution level for workers in 401(k) or similar plans is 7 percent. This is up from 6 percent in 2011, but still too low a savings rate to fund a comfortable retirement. Think about it: Retirement is likely to last roughly half as many years as a career. How can you expect to replace most or all of your income if you are only setting money aside 7 percent of that income each year? With diminished expectations for the stock market, and bond yields and savings account interest rates approaching zero, most people are not going to be able to grow their way to adequate funding. Saving more is the only way to make it work.

The reason savings rates are so low is probably that people are underestimating how much they will need in retirement. According to the Transamerica study, the median savings goal of American workers is $500,000 -- but how many younger workers understand that inflation is likely to cut the value of that amount by at least half by the time they retire?

It's no surprise that savings rates and retirement targets seem off-base, because people simply guess at them. The Transamerica Center found that nearly half (47 percent) of respondents chose a retirement target by guessing.

While the median retirement target is $500,000, the survey found that 39 percent of workers in their 60s had saved less than $250,000. That leaves them with too much ground to make up in too few years.

The survey found that most Americans plan to retire after age 65, or not at all. Also, most plan to work after retirement. Working longer may be an inevitability for many people, but it is hardly an ideal retirement planning solution. After all, it means staying healthy enough to work productively, and that is no sure thing for people over 65.

It's only natural that older workers are more focused on retirement planning than younger ones, but that is also unfortunate. The younger you are, the more powerfully you can impact your retirement savings, because you have that many more years to contribute money and benefit from investment returns. The survey found that people in their 60s are more likely to have a retirement plan and work with a financial planner than people in their 20s. The problem is that by the time you are in your 60s, your options for significantly improving your retirement funding are very limited.

Retirement planning is a very important individual responsibility. The Transamerica Center survey should be a wake-up call for Americans to take more positive action to plan for their retirements.

Read more:
Are Americans 'Winging' Their Retirement Plans?