The picture's not a pretty one. According to the report, "Boomers are under-saved, under-planned, have unrealistic expectations, and inadequately understand the retirement risks."

While some of the financial worries one might expect boomers not to have to worry about any longer include the expense of providing support to family members, including children, that's not necessarily the case, although the numbers have decreased slightly.

However, while that financial pressure may be lower than responses in earlier studies indicated, it's still there—with an increase in the number of boomers who have exchanged the financial support of children for that of grandchildren.

Related: You can make course corrections on way to retirement

Boomers are actually a bit more optimistic about overall life and economic satisfaction than they were in the 2014 iteration of the study, going from 43 percent to 47 percent, although many have not yet come face to face with the realities of retirement.

Still, 30 percent say they have postponed retirement—the same percentage that said they postponed it in the previous study.

In addition, 26 percent have stopped adding to a 401(k), IRA or other retirement plan, 26 percent found it more difficult to pay rent or a mortgage and 13 percent made an early withdrawal from a retirement plan.

Here's a look at some of the challenges that could lie ahead for boomers in retirement:

10. They're not doing all that well at saving.

While 54 percent of boomers have retirement savings, that percentage has fallen for the past four years—although fortunately those who added to their retirement savings in the past 12 months is up, marginally, from last year (to 54 percent from 53 percent), as is the percentage of those who have calculated the amount they'll need to retire (42 percent from 39 percent).

And while approximately a third of respondents say they've saved $250,000 or more, that's not necessarily enough.

According to the study, a married couple is receiving Social Security, with no employer-provided pension and with their spending at the national average level would come up short by $3,864–$12,072 each year, depending on actual savings.

They'd need to start with about $325,000, not counting an emergency fund that could be used for short-term liquidity needs, deduction of Medicare premiums from Social Security, and out-of-pocket costs for healthcare and long-term care.

9. They haven't made realistic contingency plans.

So what have boomers planned to do if the worst happens and they run out of money once they retire? Not all that much.

The biggest fallback is Social Security, with 72 percent—a tad higher than last year's 71 percent—saying they'll just downsize to live on those monthly checks.

Forty-nine percent say they'll go back to work, while 28 percent will look for help from churches, charities and social services agencies and 22 percent will turn to family members to help them out.

8. They have regrets about how they prepared for retirement.

In the words of the song, 'regrets—they have a few', with 65 percent saying they wish they'd started saving earlier and 69 percent saying they wish they'd saved more.

And 19 percent say they should have maximized an employer-provided retirement plan, but considering how few people actually have access to an employer-provided plan, that's probably why the percentage is so small.

7. They're not confident about how ready they are to retire.

Only 23 percent are confident that they'll have enough money to retire—and that number has fallen every year since the study's inception. Just 23 percent feel they've done a good job preparing for retirement, and 28 percent think they'll be able to cover their health care expenses once they retire.

Only 16 percent, though, think they've prepared well enough for long-term care expenses, and just 32 percent think they'll be more financially secure in retirement than their parents were.

6. They're worried about late-retirement problems.

They may not be all that concerned about the early part of their retirement, but boomers have plenty of fears looming in the background for the eventuality that they live into their 80s and beyond.

Chief among those fears are negative changes to Social Security, with more than three fifths of respondents afraid that the system will be changed even for current beneficiaries in a way that will cut their income.

Other fears are health care expenses, higher-than-average inflation, running out of money, not having enough money even for basic expenses and going through cognitive decline.

5. Health care costs will eat up a lot of retirement money.

At present, the study says, government data indicate that Americans age 65 and older are forking over an average of about $5,000 in annual out-of-pocket expenses for health care.

The scary thing is that that figure doesn't include the seniors who are institutionalized — and the median annual cost for a semiprivate room in a nursing home in 2016 was $82,125. Adding in these costs would substantially increase average retiree out-of-pocket expenses.

And with health care costs projected to rise 5.1 percent annually for the next 20 years—way over the U.S. inflation rate of 0.7 percent in 2015—that means that boomers without pensions, and with limited ability to wring sustainable income from their savings, could be stuck with health care costs that eat up more than 30 percent of their retirement income.

But the 28 percent of boomers think they can get by with health care costs eating up less than 10 percent of their income, while another 54 percent think expenses will be on the lower end of the 10 percent to 30 percent range could find themselves in for a rude awakening.

4. Their income expectations in retirement are unrealistic.

Nearly six in 10 respondents expect to be able to budget for their basic expenses, along with at least some travel and leisure, in retirement. And less than 20 percent are worried they won't be able to afford essentials.

But that doesn't change the fact that lots of them will find that total income from Social Security, pension and savings won't even cover basic living expenses.

3. They think Social Security will be their main source of income in retirement.

an ever-increasing number of boomers are depending on Social Security to be the main provider of income during retirement — despite all the legislators' talk about having to "reform" Social Security — most of whose plans involve cutting benefits, increasing the retirement age or some other form of diminishing the program—and despite the fact that so many boomers are worried about changes in Social Security late in their retirement that could cut their income.

This year 60 percent of respondents indicate that the earned benefit program will provide their primary income during retirement, while just 25 percent expect a defined benefit pension or an employer-provided defined contribution plan to be a major source.

"Less than 20 percent have an IRA or personal investments funded to a level where they could be expected to provide significant income," the study reports, adding, "since the average annual Social Security retirement benefit in January 2017 total[s] $16,320 for individuals, and $27,120 for an aged couple, many of the 46 percent of boomers that expect to realize annual income of $45,000 will need to save aggressively, seek professional assistance, and possibly adjust expectations."

2. They don't know how much they'll need in retirement.

A little more than half of boomers—53 percent—think they need $45,000 or less in annual income to get through retirement, while 29 percent think that number ought to be between $45,000–$75,000 a year and 17 percent are aiming for $75,000 or more.

However, as already seen, their expectations, savings and preparations indicate that a lot of them are going to have a tough time getting that much income, even at the low end, without aggressive saving, expense cutting, and finding some additional income solutions the survey terms "effective and efficient."

1. They still don't know when they'll be able to retire.

While the number of boomers who don't know when they can retire has fallen since the inception of this study in 2011, when it was highest at 38 percent, that doesn't mean that it's clear sailing these days.

In fact, while the number dropped from 2011 through 2014, hitting its lowest level at 17 percent in that year for the study's duration, it started climbing again in 2015.

This year, 21 percent say they "don't know"—but the situation is considerably worse for women. The study says, "65 percent of women who don't know when they will retire say it is because they won't have adequate savings, versus 35 percent of men."