The Powerball jackpot for the May 18 drawing continued its staggering climb to $550 million Thursday, the second largest Powerball jackpot of all time.

The Multi-State Lottery Association (MUSL) that operates the game on behalf of 45 participating lotteries, including the Louisiana Lottery, made the announcement Thursday based on a nationwide surge in sales. Before the increase, the advertised jackpot was $475 million. The cash value of the May 18 jackpot is now $350.1 million.

The jackpot was last hit on March 30 and Saturday's drawing is the 14th in the current run. Statewide Powerball sales total more than $4.4 million for the week beginning Sunday, May 12 and that number is expected to climb ahead of Saturday's drawing. Powerball tickets must be purchased by 9 p.m. that night.

The most recent Powerball jackpot won in Louisiana was in July 2010 for $85.7 million, but prizes up to $2 million can be won by matching fewer than all six numbers. So far this year, four Powerball tickets purchased in Louisiana matched all five white-ball numbers and won prizes of $1 million or more. The current draw run, which began March 31, produced one of those $1 million winners as well as one $40,000 winner and nine $10,000 winners in Louisiana.

The largest Powerball jackpot ever won is $587.5 million in November 2012, which was split between two winning tickets.

Powerball drawings are broadcast live from Tallahassee, Fla. on Official Lottery Draw Show TV stations.