DES MOINES — The biggest lottery prize in more than eight months is growing larger after no ticket matched all five numbers and the Powerball in Saturday night’s drawing. The estimated jackpot for the next drawing on Monday is $670 million. The jackpot has slowly climbed thanks to 40 consecutive drawings without a grand prize winner. There hasn’t been a bigger Powerball jackpot since a $731.1 million prize was won on Jan. 20. The odds of winning the jackpot are one in 292.2 million. The estimated jackpot amount refers to an annuity option. Most winners take cash, which for Monday's drawing would be an estimated $474.8 million, before taxes.