Want to make an extra $100 every month, indefinitely, for doing nothing?

Well, almost nothing. You just have to find a plumber and refer him or her to Bonfe Plumbing, Heating & Air Service in St. Paul. If Bonfe hires your candidate, the company will pay you — you, random member of the public who doesn’t even work for Bonfe — a cool Benjamin a month as long as that plumber stays with Bonfe.

Tempted to round up a bunch of plumbers and turn it into a nice little side business?

Good luck with that. The human resources professionals whose whole job is recruiting plumbers — or electricians, health-care providers, construction workers, financial specialists, truck drivers and many other workers in a wide variety of industries — are having a tough enough time of it themselves these days.

“We’re always recruiting, always looking for people, always working through the process and interviewing,” said Betsy Senarighi, Bonfe’s human resources manager, who is also in the market for electricians, appliance technicians and HVAC installers. Bonfe’s current limited-time deal applies only to plumbers, but the company frequently offers other recruiting specials. “It’s pretty rare that our needs are full at any given time,” she says.

Bonfe’s program is more outside-the-box than most. But as Minnesota businesses — even companies that, like Bonfe, are on the Star Tribune’s 2016 Top Workplaces list — face an ever-tightening labor market they’ve had to up their game for hiring and retaining qualified workers.

Companies are enticing employees with such incentives as signing bonuses, flexible schedules, opportunities to work remotely, and paid parental leave. Not to mention employee appreciation programs. Pizza parties. Casual Fridays — along with casual Mondays through Thursdays. Dog-friendly offices. Yoga classes. Donut Thursdays.

What about plain old money? Nationally, that hasn’t been happening, at least not so far. According to the U.S. Bureau of Economic Analysis, employee compensation (including wages and benefits) as a percentage of gross domestic product peaked in 1970 and has been declining pretty steadily since then. It’s currently near 60-year lows, barely budging since the latest recession. During that same period, corporate profits have zoomed to nearly 60-year highs.

A tightening labor market could start to push wages up. With the baby boomer generation entering retirement age — 10,000 people a day turn 65, and will continue doing so until about 2030 — the number of available employees is shrinking across a wide variety of industries.

Surprised? You’re not alone. For many people, memories of recessionary unemployment are still fresh.

But that’s so 2009. The market turned between 2010 and 2015, when the labor force grew by less than half a percent a year, the lowest rate since World War II, according to a report by the Conference Board, a business research organization. The report warns of shrinking labor supplies, even labor shortages, in the United States and other countries.

Nationally, the tightest job markets, according to the report, include occupational and physical therapy, math and science occupations, health care, religious workers, skilled labor (plant and system operators, transportation workers, machinists, installation and repair specialists), social scientists and construction workers.

State’s labor pool is shrinking

Minnesota’s May unemployment rate of 3.8 percent was lower than the national average of 4.7 percent. That trend will continue, the Conference Board report said. The number of people currently 13 to 17 years old compared to people between 50 and 64 — that is, people who will enter the workforce over the next decade versus those who will make their exit — is fewer than 1:1, the report said. That’s great news for job seekers, but not for employers, or for the state’s economic growth. A stagnant labor force also erodes tax revenue, just when an aging population needs more public services.

Demographic trends shape the overall labor market, but hard-hit industries struggle for specific reasons of their own.

For example, trade jobs are misperceived as dirty and low-paying work, Senarighi said. She pointed out that actually those workers can match new graduates’ wages without shouldering burdensome student loans. Similarly, the construction industry is hurting because so many workers left it when the market crashed.

Financial, technology and home-health businesses are growing fast and sprouting more jobs than there are candidates. Truckers are disappearing as older drivers retire.

“At one time, the truck driver was looked at kind of a cowboy out on the road, seeing the country, highly respected,” said Megan Gaffney, director of marketing for Transport Corporation of America in Eagan. “Over time that perception has fallen away.”

But truck drivers still play a vital role in the economy, Gaffney said. “If you bought it, a trucker brought it.”

Home health care services face “absolutely a battle between companies trying to get the best people,” said Sara Collison, director of human resources at Cardinal of Minnesota, a Rochester-based home health service. “We don’t want to fill the position, just because we need to, with somebody who can breathe.”

To attract skilled candidates, Cardinal concentrates on creating an appealing culture. Its “when work works” program offers flexible scheduling. “We get Monday 3-5, Tuesday 8-3 — really bizarre schedules,” Collison said. “Our schedules look really funny because we try to keep the people we have instead of denying their request.”

Also popular are accelerated training programs that let people fresh out of school catch up with more experienced colleagues. People Incorporated, a St. Paul nonprofit offering mental health services, has traditionally hired people with a few years’ career experience, but has started offering trainee positions to new graduates. “We really liked their energy and their enthusiasm and their preparedness,” said Sarah Gasparini, People Incorporated’s talent acquisitions specialist. Even people without bachelor’s degrees can train into professional-level roles over three years.

In the burgeoning technology field, “boot-camp”-style training equips people with job skills without their having to spend four years getting a computer science degree. Some companies have instituted in-house training programs.

“Even if they’re lacking some of the skills, we can train on the skills,” said Terah Ramaekers, director of talent acquisition for PowerObjects in Minneapolis. “I think a lot of organizations are starting to look at that model in general, if you find good people and they fit your core values.”

Free beer!

Employee incentives in the tech industry are also famously colorful. Minneapolis-based sports software company Sport Ngin is among a number that celebrate Fridays with in-house happy hours.

“We have free beer taps flowing,” said Jim Dahline, director of marketing. “That may extend to some of the other days of the week, but I’ll leave that to the imagination. It’s an incredible workspace.”

But wait, there’s more! Sport Ngin offers an attractive benefits package, doughnuts every Thursday and, perhaps most enticing, good salaries that stretch further than they would in, say, Silicon Valley — employees needn’t “pay $8,000 a month for an apartment in San Francisco or whatever it goes for,” he said.

Dahline has noticed the labor pool shrinking a bit over the past couple of years, but said Sport Ngin hasn’t hurt for hires — with the relative scarcity of retirement-age workers in the tech industry possibly as important a factor as free beer.

Meanwhile, some companies focus on retaining employees by simply showing them they’re appreciated, reminding them they’re integral to the organization’s success.

Cardinal of Minnesota starts all meetings by going around the room and recognizing individuals’ achievements. Transport Corporation of America authorizes truck drivers to make their own decisions on the road; if bad weather threatens driving conditions, the drivers make the call to pull over rather than being ordered to ride it out.

“We all rally around that idea that as an entire organization we’re making their lives easier, creating a positive culture, treating them with respect, calling them by a name and not by a number,” Gaffney said. “We’ve won a lot of awards for our customer satisfaction, but they’re closely related. If we can keep our drivers happy they’re going to do a better job of serving our customers.”