Read: Retirement saving not likely in 2016

Here are the top 10 factors that are determining the current, and future, picture of an aging America.

1. An exploding older population.

In 2015, 48 million Americans were 65 or older—that’s 18 percent more than only five years earlier.

But by 2030, that number will skyrocket to 74 million—and to 98 million by 2060.

Increased longevity is one factor affecting the shape of retirement—money will have to last retirees longer.

As a result many older workers are remaining in the workforce past the time when they might otherwise have taken their (figurative) gold watch and headed out the door.

2. A shrinking birth rate.

Not only are people living longer, they’re having fewer children.

That means a smaller workforce to contribute to Social Security, pensions, and other retirement plans.

According to National Vital Statistics reports, fertility rates are decreasing across all segments of the female population.

At the peak of post-World War II fertility, in 1957, women in the U.S. averaged 3.8 children over their lifetimes. In 2014, that had fallen to 1.9.

And since many elders rely on adult children to provide care as they age or become ill, the growing number of childless seniors—particularly single women—will become increasingly reliant on more distant relatives, friends, or paid helpers.

3. A more racially and ethnically diverse older population.

Non-Hispanic whites make up a lower share of the older population than they used to.

In 2000, they accounted for 81 percent of adults 65 and older, but by 2015 that had fallen to 76 percent. By 2060, they will only make up 57 percent.

But in the 60 years between 2000 and 2060, the share of Hispanics in the older population will have nearly tripled, increasing from 7 to 20 percent.

This ethnic shift, according to the report, will have far-reaching consequences, because race and ethnicity influence lifetime earnings, wealth accumulation, health status, caregiving networks, and service needs.

4. More older married women, fewer older married men.

As the life expectancy gap shrinks between men and women, there will be fewer widows, with fewer women outliving their husbands.

In spite of increasing divorce and never-married rates, older women will be more likely to live with a spouse in 2060 than they were in 2000.

However, older men will become less likely to live with a spouse over time.

That change in marital status will have a major effect on seniors, since married couples can be better off financially thanks to shared living expenses and to the likelihood of both partners receiving income—whether Social Security or a pension of some kind.

In addition, spouses provide both emotional and actual support for a partner in need of care—something those living alone can’t count on.

5. Better-educated seniors.

People born in the 1980s, the study found, are only half as likely to lack a high school diploma as those born 50 years earlier.

They’re also nearly twice as likely to have completed four years of college.

Even though they won’t hit their 70s till 2050, they’ll change the face of retirement too, because of that education.

People with better education tend to earn more, accumulate more wealth and even have fewer health problems than people who didn’t get as far in school.

6. Healthier seniors—maybe.

In the 14 years between 1998 and 2012, the percentage of adults age 80 and older in fair or poor health decreased from 43 to 34 percent.

Healthier people can work longer, as well as save money on Medicare and out-of-pocket medical costs.

The study pointed out, however, that recent health declines among middle-aged adults could stop, or even reverse, the trend.

It cited an increase from 17 to 22 percent of adults reporting fair or poor health between 1992 and 2010, with an increase among the population of diabetes.

7. Disappearing pensions, more 401(k)s.

Pension plans, as everyone knows, are disappearing. While they covered 30 percent of adults born in the 1940s and 1950s with a lifetime benefit, only 11 percent of adults born in the 1980s will have one.

Instead most will have 401(k)s, most of which have no lifetime income option.

In addition, participants must spend a lot more time focusing on a 401(k) than their elders did on pensions.

They must contribute enough money to see them through their retirement years, invest that money prudently, not take money out before retirement and keep on managing the money wisely once they do retire.

8. Women are earning more and saving more for retirement.

In the 1930s, women who worked earned only about a quarter the amount that men did.

That’s improved, although pay parity remains a distant goal—women born in the 1970s will earn just 70 percent of what their male counterparts do over their lifetimes.

While there’s still a gender pay gap, women are making more money than they used to.

That will bring them higher Social Security benefits, as well as more money in IRAs and 401(k)s.

9. Older adults are working longer.

Better health, better education and less strenuous jobs in some fields—as well as the need or desire to keep working—are all keeping people in the workplace longer.

Between 1994–2014, men working, or looking for work, aged 62–64 increased from 45 percent to 56 percent, while men aged 65–69 who were working or looking for work rose from 27 to 36 percent.

Over the same period, women working or looking for work who were aged 62–64 rose from 33 to 45 percent, while those aged 65–69 working or looking for work rose from 18 to 28 percent.

Those who work longer not only stand to increase retirement savings and accumulate additional Social Security benefits but also shorten the amount of time they’ll have to depend solely on retirement income.

10. More older adults are retiring with outstanding debt.

Older people are carrying a heavier load of debt into retirement than they used to.

That’s going to cut into what they have available to pay retirement expenses.

Between 1998–2012, the share of adults age 65 and older with household debt rose from 30 to 44 percent.

And in 2012, 24 percent of older households had an outstanding mortgage; that’s also an increase, from 16 percent in 1998. Other types of debt have also been on the increase, including credit card debt.

Not only are more people in debt in retirement, they owe more money.

The median debt level among older adults with outstanding debt increased 74 percent in inflation-adjusted dollars over the period, to $24,500.