DES MOINES, Iowa (AP) — The world’s largest lottery jackpot has grown to $1.5 billion because of continuing strong Powerball ticket sales.

Lottery officials increased their estimate of the huge jackpot for the second day in a row Tuesday because of immense interest in the prize.

The record-breaking Powerball jackpot could grow higher before tonight’s drawing if ticket sales continue to exceed expectations. Officials reassess the jackpot estimate daily.

The huge jackpot has forced many convenience stores to bring in extra clerks to keep lines moving, hoping that people wanting.

“When the jackpots get big like this, it creates a frenzy,” said Brian Johnson, vice president of finance at Casey’s General Stores, which runs 1,900 stores in 14 states.

The odds of matching all six numbers to win the jackpot are one in 292.2 million.

The $1.5 billion prize would be paid in annual payments over 29 years. Or the winner could opt for a lump-sum payment of $930 million.

Whoever wins will have to pay 39.6 percent of the prize in federal income taxes, and any state taxes. Lottery officials expect at least 80 percent of the 292.2 million number combinations will be purchased before Wednesday’s drawing.