DES MOINES - Powerball players have a shot at the nation's eighth-largest lottery jackpot, but they should keep in mind that their dreams of riches likely won't become a reality.

The odds of a winning ticket in Saturday night's drawing for a $478 million prize are incredibly small: one in 292.2 million.

It's because of those odds that there hasn't been a winner since May 7, when a family from New Jersey won a $429.6 million jackpot. The nation's biggest prize was January's $1.6 billion Powerball jackpot.

The drawing will take place at 10:59 Eastern time, when tumblers filled with balls will select the five numbers and single Powerball. If there isn't a winner, the jackpot will increase and another drawing will be held Wednesday.

HOW DID WE GET HERE?

No one has matched all the numbers since the May 7 drawing, when a New Jersey family won a $429.6 million prize. Drawings are held twice a week, and every one that passes without a winner means the prize grows larger, fed by the purchase of more $2 tickets.

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HOW DOES THIS PRIZE COMPARE?

It's big but less than a third the size of the record $1.6 billion Powerball jackpot won in January by players in California, Florida and Tennessee. At $478 million, the prize would be the fifth-largest in Powerball history and the nation's eighth largest overall, just behind a $536 million Mega Millions prize won July 8.

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ARE BIG JACKPOTS MORE FREQUENT?

Yes, and for a simple reason: math. Last year, officials at the Multi-State Lottery Association, a group of state lotteries that oversees Powerball, changed the odds of winning from 1 in 175 million to 1 in 292.2 million. They wanted to generate bigger jackpots that would increase sales and produce even larger prizes. Thanks to the change, three of the largest Powerball prizes, including the current jackpot, have occurred in 2016 - a tally that could grow with five months left in the year.

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HOW DOES THE DRAWING WORK?

The drawing is held Wednesday and Saturday at 10:59 p.m. Eastern time, usually in Tallahassee, Florida. One tumbler contains 69 white balls and another holds 26 red balls. In about 30 seconds, the machines select five of the white numbered balls and one red ball.

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WHAT ARE THE PRIZE OPTIONS?

Jackpot winners can choose between an annuity paid out over 29 years or a cash option. The big jackpot prize that gets most attention refers to the annuity, but most winners choose the cash option. To the lottery, the payout is the same.

The difference is whether the winner takes the cash or agrees to have that money placed in a low-risk investment with a guaranteed payment made annually. Annuities have tax advantages and lessens the risk a winner will blow through the money, but many people think they can earn more money by investing the winning themselves.

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WHAT ABOUT THOSE TAXES?

State and federal taxes vary by state, but in general, winners pay about half the cash amount. So, if someone wins Saturday and opts for the $330.6 million cash option, they'll need to scrape by with roughly $165 million after taxes.

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THE ODDS AGAIN?

It's hard to comprehend - one in 292.2 million. One way to think about it: When there finally is a winner, it almost undoubtedly won't be you.