RIO DE JANEIRO — The International Olympic Committee calls its president and executives "volunteers."

They receive no salary but do collect substantial cash handouts: a $250,000-annual allowance for "volunteer" president, Thomas Bach, and $900 per diems for executives on IOC business.

However, when IOC spokesman Mark Adams said Thursday that "volunteers are the backbone of the games" he wasn't talking about his bosses in the Olympic movement.

There's another variety of volunteers who are the lifeblood of every Olympics — ones who aren't ensconced in the lavish hotels, wined and dined by the great and the good, and enjoying the best seats at any event in Rio.

They're the people who pay their own way to Rio — often crossing the globe at great personal expense— while finding and funding their own accommodation.

There are no per diems for these volunteers — just food when they work — and they fill often thankless roles far away from the sporting action, from manning information desks to driving people around.

It's little wonder some don't stick around after collecting the head-to-toe leisurewear uniform. Some 15,000 volunteers a day aren't showing up for their unpaid but essential jobs.

"Of the 50,000 volunteers involved in the delivery of the Olympic Games, we have an average attendance rate of just over 70 percent," Rio organizers told The Associated Press. "This number allows us to operate at a comfortable level as some volunteers not showing up was factored into our plans."

Organizers scrambled to add another 180 drivers to the workforce on Monday as shortages hit the transport network, Rio Games spokesman Mario Andrada said. It was a paid driver on the media bus that was attacked by stones in Rio, but other drivers are exposing themselves to potential dangers are being paid nothing.

It's a risky business relying on a workforce for an event that isn't under contract.

"If we have a tough day," Andrada said, "next morning some of them don't show up."

The IOC could afford to pay volunteers, given the organization's revenue is set to reach $5.6 billion for the four-year period ending in 2016, while sitting on cash reserves of $874 million.

But the IOC has stressed it's not an issue of setting aside $100 million, for example, to ensure every games worker is paid but preserving the "spirit of volunteerism."

The IOC said it redistributes more than 90 percent of its income, equating to $3.25 million a day, said Adams, the organization's paid media chief in Rio.

And Adams points out: "Even the president is an unpaid volunteer of this organization. The IOC members are all unpaid volunteers."

But spending three weeks in Rio for pre-games meetings and the Olympics would earn 14 members of the IOC executive board more than $20,000 each. The next tier of regular IOC members can rake in around $10,000 in per diems at an event where so much free food and drink is provided on top of their hotels.

The disparity between the IOC's paid volunteers and the volunteers who drive them around and tend to their needs is clear.

But games organizers are oversubscribed with willing volunteers, rather than having to beg people to work for nothing.

"The number of volunteers we have and the great spread of volunteers we have means we can't fund them in that way (like IOC members)," Adams said. "They get other kind of perks of course and they get the perk of being at the games. ... "They get a great deal out of being volunteers and being a member of the Olympic movement for that short period is tremendously rewarding."

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