Let's say you count on earning $360,000 a year to take care of your many dependents, pay the bills, and stay afloat.

You got lucky from 2010 to 2014, when you averaged about $552,000 a year. You were so flush that, in 2015, you gave your dependents a little extra, about $61,100.

But last year, you saw your earnings slashed to $36,800. And to make matters worse, this year your earnings will be less, way less.

And all along, however, the bills have to be paid, only they'll be higher this year.

This is what Philadelphia's Pension Fund is going through, except in the hundreds of millions of dollars, and city taxpayers should be concerned.

"These are likely to be big and disturbing numbers," Donald J. Boyd, senior fellow at the Nelson A. Rockefeller Institute of Government, said of Philadelphia's situation.

And the future looks even worse.

"If you think you will be in Philadelphia in five years, this is bad news," Boyd said, pointing out that taxpayers will be on the hook to make up the losses.

After the Great Recession ended in 2009, the Pension Fund had five good years, averaging a return of 12 percent on investments in the neighborhood of $4.6 billion. The Pension Fund was feeling so good that last summer it shared - as mandated by a 2007 law that Mayor Kenney authored while on City Council - the wealth with three-quarters of its 30,000 pensioners, doling out a total of $61 million to retirees with at least 10 years in the system.

The good times, however, ended suddenly.

Fiscal year 2015, which ended June 30, finished with a return of only .8 percent: $37.4 million. It had originally assumed a return of 7.8 percent, earning $365 million.

And Fiscal Year 2016 is looking much worse, according to the Pension Board's estimate.

By the end of December (six months into Fiscal Year 2016), the $4.68 billion investment fund had lost 4.75 percent of its value, said City Finance Director Rob Dubow. That's roughly $220 million.

Although the city is still anticipating a return of 7.8 percent this fiscal year and beyond, it will be on a smaller investment fund.

But some pension investment experts say that's unlikely.

The city's forecast of "7.8 is overly optimistic. I don't think it's in the cards long-term," said Rick Dreyfuss, a fellow at the Manhattan Institute's Center for State and Local Leadership who has an expertise in public pensions. A return of 6.5 percent is more reasonable.

That 1.3 percent difference amounts to roughly $60 million.

To be fair, other municipalities and state governments also assumed returns of better than 7 percent in Fiscal Year 2015, but saw smaller returns.

Those returns, however, were just not as small. New York City, for example, had a return of 3.3 percent; Oregon, 4.3 percent; Texas, 3.9 percent; Maryland, 2.7 percent.

So why were the city's investments worse than that of other public pension funds?

"It was a rough year in the market in general," Dubow said. "We monitor managers throughout the year and some were terminated."

Boyd, the senior fellow at Rockefeller, was harsher in his assessment.

"Performance was abysmal across the board, but it looks like Philadelphia takes the cake for worst as far as I can see," Boyd said.

All the while, the Pension Funds' obligations remain. And when the fund does not earn the $360 million to pay its pensioners, the city has to make up the difference.

"When you don't get the budgeted projected return, that amount has to be made up by taxpayer contribution," David L. Cohen, who has called pensions the city's biggest crisis, said last week. "It is eating alive the ability of any city and mayor to make any investments they want to make" in the city.

Kenney is aware of the looming problem.

"We're working on a couple different scenarios that we would like to present to Council and our labor unions and they understand the same stuff we understand and that is the Pension Fund is not in a good position, situation and the markets are volatile," Kenney said in an interview late last week. "But it's a discussion and it's a collaboration and it's not a dictation."

It is not yet clear how much more the city will have to pay into the Pension Fund this coming year - the losses are spread out over 10 years so the millions in investment loss doesn't hit all at once.

The city's actuary report that breaks down all the numbers will not be ready until the end of February, Dubow said.

For Fiscal Year 2016, the city estimates it will have to chip in $612 million. And for the following year, it forecasts paying $621 million.

But even that number is too optimistic, given market trends.

"It's likely that the new payments [to the Pension Fund] will be higher than the payments shown in last year's payment schedule to compensate for the lower than anticipated earnings," Dubow said.

Brad Woolworth, the Pension Board's chief investment officer, said he has taken some steps to protect the Pension Fund from further erosion.

He has moved 5 percent of the fund away from riskier investments and into cash reserves.

City Controller Alan Butkovitz, who sits on the pension board, questioned whether that strategy was enough.

If the market contracts 20 percent, as some economists have predicted, the impact on the Pension Fund would be "a catastrophe," he said during Thursday's pension board meeting.

"If there begins to form a consensus view that we are halfway down to a 20 percent decline," he said, "isn't there a better answer than sitting there and riding it down?"

The Pension Fund was already in a dire situation before its investments went south.

It only has 46 percent of the money it is supposed to have in the fund. To be healthy, the fund needs to be at $10.5 billion.

The smaller yield in its investments will only exacerbate that.

cvargas@phillynews.com

215-854-5520@InqCVargas